HO-76
Sharon S. Bale, Richard E. Durham, Robert G. Anderson, and Robert L. Geneve
Perennial flowers are hardy plants that occupy a permanent place in the garden and return year after year. Perennial flowers bloom sometimes for one week and occasionally for as long as 10 weeks. Some desirable perennials are not grown for their flowers but for their foliage.
Perennials are generally used in small numbers, while annual flowers are used in large numbers to create massive displays of color. A typical goal for a perennial garden is to have plants in bloom, or producing some type of display, throughout the growing season even though an individual plant may be colorful for only a short period of time.
Choosing perennial plants requires more thought and knowledge than choosing annual plants for the garden. This is because there are so many perennials, and they will be a relatively permanent addition to your landscape. Annual flowers generally tolerate a wide range of conditions, while perennial plants may have specific soil and light requirements.
Perennials should not be considered a low-maintenance plant for the flower garden. No plant is that perfect. Most perennials, if not all, require some type of specific care, such as deadheading (removing spent blooms), cutting back, or division to maintain the vigor of the plant. In addition, weeds are a constant problem in a perennial flower garden.
A list of the "best perennials" is almost impossible to compile. There are many choices, and the "best perennials" depend on the likes and dislikes of the gardener.
This publication lists selected perennials. Most perform well in Kentucky, while others may not be as reliable or hardy, or they may have other problems that make them less desirable. These plants prefer a sunny location; most perform best in a full-sun location, and some tolerate partial shade conditions. For information on perennials that thrive in shade, consult this publication's companion piece, HO-77 Perennials for Shady Locations.
A border planting is one of the most common uses of perennials. A gardener usually "plans" the border so different plants flower at different times. Choosing a variety of plants to bloom in succession provides a good visual display throughout the growing season.
Smaller perennials are suitable for use in rock gardens, along the edge of a flower bed, or in small areas where they can be seen easily. Many perennials are grown in the background of the garden and are used as cut flowers.
The most common mistake made when planting an entire perennial border is not allowing enough space for the mature plants. Perennials purchased in gallon containers may fool a gardener about their potential size. Most plants can be easily moved to provide more room. It is just a case of more work for the gardener.
Be aware that the perennial garden will change with time. No matter how experienced the gardener, no matter how exact the planting plan, a perennial garden will constantly change and yield surprises. Tall plants won't be as tall as you had hoped; yellow blooms won't be as bright as you expected; even your favorite plant may not make it through the winter. More commonly, you may run out of garden space. Adding more space to your garden can give you a chance to try new cultivars and different plants.
You will notice that most plants listed in this publication are designated as having few pests. However, the overall health of the perennial flower garden can drastically affect the need for pest control. A very practical and effective approach to pest control involves a process known as integrated pest management, or IPM. The IPM approach is multifaceted and much broader than simply applying pesticides when problem organisms are present.
One of the main tenets of IPM is to select plants with natural pest resistance such as many of the species and cultivars listed in this publication. However, plants should also be selected based on the environment in which they will grow, such as sunny versus shady conditions, wet versus dry sites, or acid versus alkaline soils. These environmental recommendations are often given in the Performance section of the plant descriptions. Placing a plant in an improper site will result in poor plant growth that often invites pest problems down the road.
Good cultural practices, another important part of IPM, include choosing the right plant for a particular site, preparing the planting site, placing the plant properly, and maintaining the plant with correct practices involving irrigation, fertilization, mulching, sanitation, and division or separation of overgrown plants.
Proper mulching and sanitation yield many benefits. Organic mulches applied regularly to the soil promote the growth of beneficial soil organisms, regulate soil temperature, conserve soil moisture, and reduce competition by weeds. Regularly removing dead or dying plant material and cleaning up the garden in fall and spring will greatly reduce the number of insects and diseases that are present and may potentially overwinter in the landscape. When these activities are carried out correctly, the perennial flower garden will rarely need treatment with pesticides.
When pest problems do arise, the issue can often be resolved through non-chemical means, or the use of chemicals or biological control agents that are very specific to the targeted pest and less likely to interfere with the natural ecology of the perennial garden. Your county Extension agent is often able to help with diagnosis of the problem and can prescribe a treatment to remedy the pest situation.
Plant names—The scientific and common names of selected perennials are listed in the chart. Common names vary depending on location. Therefore, scientific names are arranged alphabetically for ease in finding particular plants.
The scientific name (genus and species) is important because gardeners seeking information about a specific plant will need this name for most reference books. In some cases, scientific names have changed; an effort has been made to list the new scientific name with the older, more familiar scientific name. Plant names are based on those used in Herbaceous Perennial Plants by Alan M. Armitage. Scientific names are hard to learn but make it easier to find information in perennial books and catalogs.
Typical common names are listed as well, but these names may vary from region to region and may be confusing.
A specific cultivar (cultivated variety) is often listed with the scientific name or mentioned in the comments. This indicates that the cultivar is superior to the "wild-type" genus and species. Plant breeders working on perennial flowers are producing more and more choices, and many of them are worth the extra expense to purchase or the extra time to find.
If your favorite cultivar is not listed, be assured it was not left out intentionally. It is nearly impossible to keep up with all the good cultivars. Contact your county Extension agent about favorite plants that have proven their worth to you.
Color—Most perennials are available in a narrow range of colors. Bicolor blooms are those with two colors.
Bloom season—The bloom season listed is the typical time to expect the perennials to flower. Weather conditions affect the exact date of bloom. Therefore, a comment relative to season of bloom seems more appropriate than giving specific months.
Diseases and insects—Most of the perennials listed have no serious disease or insect pests. The plants generally tolerate pest problems and require no chemical treatment. The age-old practices of garden cleanup and sanitation are important in pest management.
Performance—This category provides tips on plant performance and general maintenance that encourages plant vigor. Warnings concerning invasiveness and other cultural problems are also listed here.
Propagation—Many perennials can be produced from seed. Propagation of perennials from seed is slow, and some may require several years before they are mature enough to bloom. A gardener may lose patience and/or plants before those propagated from seed mature to flower production.
Division is a common way perennials are produced. There may be specific times during the season when division is most successful for some plants, while others can be divided anytime. A general rule is, "If the plant blooms in the spring, divide it after bloom or in the fall. If the plant blooms in the fall, divide it in the spring."
Cuttings of perennials may root easily and produce large numbers of small plants in a short time. The only requirements are appropriate growing media and a typical cutting propagation environment. Although cutting production may be simple, the small plants may require several years before blooms are produced.
Comments—This section contains specific information about the species or hybrids. Cultivar names may be listed. Uses of the plant are mentioned. Comments are made on life expectancy of the plant if it is short.
| Name | Flower Color | Height | Season | Pests | Uses | Propagation | Performance/Comments |
| Achillea x 'Coronation Gold'
Yarrow
|
yellow | 2-3' | summer | few | border, cut, dried | division in spring or fall, cuttings in spring or early summer | Performance: Achillea performs
well in poor soil; it is easily overwatered. Division is recommended every
2-3 years to maintain plant vigor. Bloom size decreases as season progresses.
Excessive fertilization causes the plant to become leggy.
Comments: 'Coronation Gold' may require staking. The flat-headed blooms are long-lasting cut flowers. They will dry and retain their color. 'Coronation Gold' is a hybrid of A. filipendulina and considered one of the best choices for the garden. |
| Achillea x 'Moonshine'
Moonshine Yarrow |
yellow | 1-2' | summer | few | border, cut, dried | division in spring or fall, cuttings in spring or early summer | Performance: Performs similarly to A.
'Coronation Gold' except the plant is more compact and does not require
staking. Does best during seasons of little rainfall.
Comments: 'Moonshine' is a hybrid of A. clypeolata and A. taygetea. A. taygetea is susceptible to many foliar diseases that are promoted during hot, humid weather. |
| Achillea millefolium
Common Yarrow |
red, white, pastel shades | 1-3' | summer | few | border, cut | division in spring or fall, seed | Performance: This plant may become invasive.
Comments: 'Summer Pastels' is an All-America Selection. It has a wide range of colors. When started from seed, it may not bloom well the first season. As cut flowers they take up water rapidly. |
| Allium tuberosum
Garlic Chives |
white | 1-2' | late summer | few | border, cut, herb | division in spring or fall, seed | Performance: The plant is very hardy
and produces bloom at a time when most other perennials do not bloom. To
control the spread of this plant, remove the declining blooms. Can be invasive.
Comments: The foliage is edible and used for its mild garlic flavor. |
| Amsonia tabernaemontana Willow Amsonia | pale blue | 3-4' | late spring, early summer | few | border | division (spring or fall), cutting, seed | Performance: Reliably hardy and will
spread into a large clump.
Comments: Related species: A. hubrectii is more dwarf. |
| Anemone x hybrida
Japanese Anemone
Related species: A. huphensis, 'Robustissima' |
white, pink, violet | 3-4' | late summer, fall | few | border | division in spring, root cuttings, seed | Performance: The light, airy, pastel
blooms are attractive in the fall.
Comments: Often sold under the name Anemone japonica. Many of the cultivars available are probably hybrids. Some cultivar choices are: 'Lady Gilmour'--16" tall, double pink; 'Luise Uhink'--24" tall, double white; 'September Charm'--30" tall, single pink; 'Margarette'--36" tall, semidouble pink; 'Honorine Jobert'--36" tall, single white. |
| Anthemis tinctoria
Golden Marguerite |
yellow | 3' | midsummer | few | border, cut | division in spring or fall, seed | Performance: Plant performs well until
late summer when it may become unsightly. This plant does fine in dry, average
soil. Plant should be cut back after flowering to promote vigorous growth.
Division every 2-3 years is necessary to maintain vigor. Plant may need
staking.
Comments: 'Moonlight' blooms heavily, and cut flowers last a long time. |
| Aquilegia x hybrida
Hybrid Columbine |
blue, white, red, pink, yellow | 18"-3' | spring, early summer | leaf miner | border | seed, division in late summer | Performance: Does well in partial shade.
Requires excellent drainage but does not tolerate an overly dry soil.
Comments: There are several species of Aquilegia. The hybrids are popular because of the wide range of colors available and the large upright blooms. |
| Arabis albida
Wall Rock-cress |
white | 12" | early spring | aphids | edging, rock garden | division, cuttings, seed | Performance: The plant tends to "burn
out" in hot, humid weather. It may be considered a short-lived perennial.
Pruning in late spring helps promote vigorous growth.
Comments: Also known as A. caucasica. Some cultivars available are 'Flore Pleno'--double white flowers; 'Snow Cap'--6" tall, white flowers; 'Variegata'--cream-yellow, variegated foliage. |
| Armeria maritima
Common Thrift |
pink, lilac, white | 6-12" | early summer | few | border, rock garden | division, seed | Performance: The gray-green clump of
foliage is evergreen. Prefers a dry location. A wet location causes the
plant to rot. Divide often to promote flowering.
Comments: Several species and cultivars of thrift are available. |
| Artemisia ludoviciana
White Sage |
gray foliage | 2-4' | all season | few | border, dried | division, seed | Performance: This plant can be very invasive.
It tolerates a wide range of soil conditions but will not tolerate a wet
location.
Comments: The foliage can be harvested throughout the growing season and dried for use in wreaths or arrangements. 'Silver King' and 'Silver Queen' are two of the cultivars available. |
| Artemisia schmidtiana 'Silver Mound'
Silver Mound Artemisia |
gray-green foliage | 6-8" | all season | few | border, rock garden | cuttings | Performance: Under extremely hot conditions,
the plant may become leggy and unattractive. Promote new growth by lightly
shearing the plant.
Comments: This plant is grown for the fine-textured foliage. |
| Asclepias tuberosa
Butterfly Weed |
orange | 1-2' | summer | aphids | border, cut | seed, root cuttings | Performance: The plant is slow to emerge
in the spring so care should be taken to avoid disturbing it. It is difficult
to transplant. The plant is native in Kentucky and performs well.
Comments: The flowers are commercially produced as a cut flower. There is a great deal of color variation related to seedling variation. Repeat bloom is promoted if the initial blooms are removed as they begin to decline. |
| Aster x frikarti 'Wonder of Staffa'
Frikart's Aster |
lavender | 2-3' | summer to fall | powdery mildew | border | division | Performance: Needs staking. Give some
winter protection if extremely cold and no snow cover. Prefers well-drained
soil. Pinch plant in spring to encourage abundant flowers.
Comments: 'Monch' flowers are deep blue and have an extra row of petals. The plant is shorter than other cultivars. |
| Aster novae-angliae
New England Aster |
pink, white, red | 3-5' | late summer | powdery mildew | border, cut | division | Performance: May need staking. May have
longer vase life than A. novi-belgii
Comments: Many cultivars are available. |
| Aster novi-belgii
Michaelmas Daisy |
violet, white, blue | 1-6' | late summer | few | border, cut | division | Performance: Fertilize sparingly. Divide
every other year. Taller types require staking.
Comments: Many cultivars are available. |
| Aurinia saxatilis
Basket of Gold, Perennial Alyssum |
yellow | 1' | spring | few | border, edging, rock garden | division in fall, seed, cuttings in spring or fall | Performance: The gray-green foliage may
become unsightly after bloom. Cut back after flowering. Not long-lived.
Requires excellent drainage.
Comments: Also listed as Alyssum saxatile. Many cultivars are available. |
| Baptisia australis
False Indigo |
blue | 3-5' | late spring | few | border | seed, division in late fall or early spring | Performance: Because of its shrub-like habit, this plant is attractive
in the garden after bloom. Even moisture is best. Average, well-drained
garden soil is adequate.
Comments: The charcoal-gray seed pods are attractive in dried arrangements. No special care is required to dry them. Dependable, low-maintenance plant. |
| Belamcanda chinensis
Blackberry Lily |
yellow, orange (spotted blooms) | 3-4' | summer | iris borer | border | seed, division | Performance: Average garden soil is fine.
Each bloom lasts only a short time, but the plant produces a large number
of buds.
Comments: The seeds give the plant its common name. Birds often spread this plant to other parts of the garden. The foliage is very similar to that of an iris. |
| Bergenia cordifolia
Bergenia, Pigsqueak |
pink, red | 1-2' | spring | few | border, ground cover | division in spring, seed | Performance: The glossy foliage is practically
evergreen. The foliage is more showy than the flowers. Tolerates a wide
range of conditions. During the winter, the foliage becomes red or bronze.
Comments: The plants perform well in semi-shade also. Many cultivars are available. |
| Boltonia asteroides
Boltonia |
white, pink | 3-4' | late summer | few | border | division in spring | Performance: Does not require staking
when grown in full sun. Performs best in deep, moist, organic soils. Does
not seem to mind drought. Divide every 3-4 years.
Comments: Seeds of 'Snowbank' do not come true to the cultivar. 'Pink Beauty' is superior to 'Snowbank'. |
| Campanula carpatica
Carpathian Harebell |
blue, white | 4-12" | early spring | few | border, cut | division in spring or fall, seed | Performance: Plant prefers an evenly
moist soil.
Comments: Many cultivars are available. |
| Campanula glomerata
Clustered Bellflower |
purple | 1-2' | summer | few | border | cuttings after bloom, seed | Performance: Prefers a moist soil and
tolerates a wet location. The blooms last for approximately 3 weeks. May
need staking.
Comments: Lasts well as a cut flower. Some of the cultivars available: var. acaulis --3-5" tall, violet blue; 'Joan Elliott'--12-14" tall, violet blue; 'Superba'--12-14" tall, violet, tolerates heat. |
| Campanula persicifolia
Peach-leaf Bellflower |
blue, white | 2-3' | late spring, early summer | few | border, cut | division, cuttings, seed | Performance: Prefers a well-drained,
average soil.
Comments: Tolerates partial shade. Several cultivars are available. Re-blooms if cut. Good for cutting. |
| Centaurea dealbata
Persian Cornflower |
pink, white | 2-3' | late spring, early summer | few | border, cut | division | Performance: It is best to cut the declining
blooms to maintain the compact habit of the plant.
Comments: Centaurea hypoleuca 'John Coutts' was thought to be a cultivar of C. dealbata. Whether it is or not doesn't matter--this is a good cultivar. |
| Centranthus ruber
Red Valerian, Jupiter's Beard |
pink-red, white | 1-3' | summer | few | border, cut | seed, cuttings | Performance: Prefers a well-drained soil
that is slightly alkaline.
Comments: Flowers most of the summer. |
| Cimicifuga racemosa
Black Snakeroot, Cohosh |
white | 5-8' | late summer | few | border | seed, division | Performance: Prefers a rich, moist soil.
Fills in rapidly and does well at the back of the border. The plant has
a deep root system and does not divide well. Seed may be difficult to germinate.
Comments: The tall, white spire blooms last for several weeks. |
| Coreopsis grandiflora
Tickseed |
yellow | 2-3' | early summer | few | border, cut | seed, division | Performance: To keep this plant in good
condition, old, dead flowers must be removed. The plant produces many blooms
but requires heavy maintenance.
Comments: 'Early Sunrise' requires less maintenance. This one will bloom the first season, but it still performs better the second or third season. |
| Coreopsis verticillata
Threadleaf Coreopsis |
yellow | 1-2' | summer | few | border | seed, division | Performance: Generally does not require
much maintenance.
Comments: 'Moonbeam'--12" tall, primrose yellow flowers are produced most of the summer. This is an excellent cultivar and requires no maintenance. 'Zagreb'--18" tall, deep yellow flowers. Other cultivars are available. |
| Crocosmia x 'Lucifer' | red | 2½-3' | summer | mites | border, cut | division | Performance: While other Crocosmias
may not be as reliably hardy, this particular cultivar performs quite well.
May benefit from division every 2-3 years.
Comments: 'Lucifer' is a result of an interspecific hybrid of Crocosmia and Curtonus paniculatus. Seed pods are also attractive and useful in flower arrangements. |
| Delphinium x elatum
Hybrid Bee Delphinium |
white, blue, lavender | 2-8' | late spring | few | border, cut | seed | Performance: A cool season perennial
that generally lasts only 1-2 years in Kentucky. Requires an excellent garden
site.
Comments: Many beautiful cultivars are available, but none are reliable in Kentucky. |
| Dendrathema x morifolium
Garden Chrysanthemum, Fall Blooming Mums (formerly Chrysanthemum morifolium) |
yellow, bronze, lavender, white | 1-2' | fall | aphids, leaf hopper | border, cut | cuttings, seed, division in spring | Performance: Some cultivars require pinching
until July to keep the plants compact and attractive. Soil should be fertile.
Ideally they should be divided each spring.
Comments: Even though listed as hardy, some cultivars may not survive our winter conditions. |
| Dianthus gratianopolianus
Cheddar Pinks
|
rose, pink | 9-12" | spring, summer | few | edging, rockery | seed, division, terminal cuttings | Performance: May be short-lived, so divide
every 2-3 years. Full sun, excellent drainage, slightly alkaline soil.
Comments: 'Bath's Pink' has soft pink flowers, 1" across, fringed. 'Tiny Rubies' has double, deep-pink flowers. Related species: D. allwoodii, D. deltoides, and D. plumaruis. |
| Doronicum caucasicum
Leopard's Bane |
yellow | 1' | spring | few | border, cut | seed, division | Performance: Must have a moist soil.
The foliage declines during hot weather.
Comments: Also listed as D. cordatum. Not a long-lived perennial in this area. May perform better in partial shade. |
| Echinacea purpurea
Purple Coneflower |
reddish purple, white | 3-5' | summer | powdery mildew | border, cut | seed | Performance: This plant blooms for an
extended period in the garden. Removal of old flowers promotes bloom production
and prevents reseeding. Tolerates a wide range of soil conditions.
Comments: 'Bright Star' has brilliant rose flowers, and petals extend horizontally. E. purpurea alba has white flowers with bronzy orange, domed cones in the center. All are excellent cut flowers. |
| E. tennesseenis Tennessee Coneflower | Mauve | 1½-2' | summer | few | border, cut | seed, division | Performance: Flower petals are more narrow
than E. purpurea; performance is equal.
Comments: A southeastern native and on the Federal Endangered Species List. Seeds and plants are available from reputable sources. |
| Echinops ritro 'Taplow Blue'
Globe Thistle |
steel blue | 2-3' | summer | few | border, cut, dried | seed, division | Performance: After bloom the foliage
begins to die back. New growth appears in the fall. Requires no special
soil conditions.
Comments: Large, spiny leaves resemble a thistle, but these plants are not invasive like thistle. Any unwanted seedlings can be easily pulled from the garden. The flowers can be dried. |
| Euphorbia epithymoides 'Polychroma'
Spurge |
yellow | 1-2' | early spring | few | edging, border | division | Performance: Prefers a poor, dry soil.
Comments: Foliage turns crimson-red in the fall. Forms brilliant yellow mound in early spring. Relative of poinsettia. |
| Euphorbia myrsinites
Myrtle Euphorbia, Donkeytail Spurge |
yellow | 8-12" | early spring | few | border, rock garden | seed, division, cuttings | Performance: Prefers a poor, dry soil.
Comments: Like all Euphorbias, this plant has a milky sap that irritates the skin, possibly severely. The plant is grown for the trailing effect of the gray-green foliage which is practically evergreen. |
| Filipendula ulmaria
Queen of the Meadow |
white | 3-4' | summer | few | border | seed, division | Performance: Prefers a moist soil. In
full sun the foliage tends to "burn" and look unsightly.
Comments: Several cultivars are available. Related species have pink flowers. |
| Gaillardia x grandiflora
Blanketflower |
dark red with yellow tips | 1' | summer | few | border, cut | seed | Performance: Prefers a dry, well-drained soil that is not overly
fertile. Cut the declining flowers to encourage more blooms.
Comments: 'Goblin' is a common cultivar. |
| Gaura lindheimeri Gaura | white, pink | 3-4' | summer | few | border | seed, division | Performance: Plant tolerates adverse
conditions, but the leggy habit may not be desirable.
Comments: Introduction of new cultivars with improved plant habit. |
| Geranium sanguineum
Cranesbill |
violet, red | 1' | late spring | few | edging, border | seed | Performance: Requires a well-drained
soil. Does not require frequent division.
Comments: Many other species and cultivars are available. These plants can spread over 2 feet. |
| Geum hybrids
Geum |
yellow, orange, red | 1-3' | late spring | few | border, cut | seed, division | Performance: Prefers a well-drained soil
high in organic matter.
Comments: Several cultivars are available. This is not a long-lived perennial in Kentucky. The plants prefer a cooler climate. |
| Gypsophila paniculata
Baby's Breath |
white, pink | 2-3' | summer | few | border, cut | seed, terminal cuttings | Performance: Prefers a well-drained soil
and does not tolerate wet feet. The plant produces large, fleshy roots.
Once established the plant resents disturbance.
Comments: Several cultivars are available. Cutting the blooms tends to promote re-bloom. Tends to be a short-lived perennial in this area. |
| Heliopsis helianthoides scabra 'Summer Sun'
Heliopsis |
yellow | 3-4' | summer | few | border, cut | seed | Performance: Does well at the back of
the border. No staking is required. No special soil conditions are needed.
Comments: The mound of double blooms produced by this plant can be very showy, and it flowers much of the summer. Other cultivars are available, but this particular one has performed well. The color is very bright. |
| Hemerocallis hybrids
Daylily |
yellow, orange, white, pink, salmon, bicolors | 8"-3' | early summer | aphids, leaf spot | border, mass planting | division | Performance: Easy to grow and a good
addition to the garden. Tolerates semi-shade. Although each bloom lasts
only one day, numerous buds are produced.
Comments: These plants are available in a wide range of bloom colors, forms, plant heights, and bloom sizes. Thousands of cultivars are available, all of which have something to offer the flower garden. Mid- to late June is considered the prime blooming time for Hemerocallis. 'Stella d'Oro' is one cultivar that blooms for a long period of time. |
| Heuchera sp.
Coral Bells |
pink, red, white | 8-18" | late spring | few | border, mass planting | seed, division | Performance: Requires a well-drained
soil. Divide every 3 years. May perform best in a semi-shade or shade location.
The dainty blooms can add a great deal to the landscape.
Comments: H. sanguinea cultivars recommended include 'Chatterbox', 'Mt. St. Helens', and 'June Bride'. H. x brizoides cultivars recommended include 'Coral Cloud', 'Pluie de Feu', 'White Cloud', 'Bloom's Variety', and 'Tattletale'. Other Dan Heims hybrid introductions worth finding include 'Ruby Veil', 'Ruby Ruffles', 'Regal Robe', 'Purple Sails', and 'Pewter Veil'. |
| Heuchera micrantha
Small-flowered Alumroot
|
white | 8-10" | late spring | few | border, edging | division, seed | Performance: Cultivar 'Palace Purple'
is grown more for the effect of the foliage rather than the flowers, which
are often removed.
Comments: 'Purple Palace' is a readily available cultivar. H. americana 'Purple Petticoats' has a solid dark purple leaf with ruffled edges. Seedlings may vary widely in foliage color. Cultivars should be propagated by division. |
| Hibiscus moscheutos
Rose Mallow |
white, red, pink, bicolors | 3-8' | summer | Japanese beetles, cater-pillars | border | seed, division | Performance: The foliage dies back to
the ground in winter. One plant will eventually fill a 4-foot-square area.
Comments: This plant produces blooms that average 6-8" in diameter. The plants are very showy. Plants grown from seed take several years to reach a mature size. Allow plenty of room for these plants. The 'Frisbee' hybrids are about 4 feet tall and are a better choice than older forms that require staking. |
| Iberis sempervirens
Candytuft |
white | 6-10" | early spring | few | border, edging | seed, cuttings. Most of the cultivars are propagated by cuttings. | Performance: Requires a well-drained
soil. May suffer winter dieback in full sun. Prune after bloom to maintain
compact growth habit.
Comments: This is a common perennial used for spring show in much the same way as creeping phlox. Some of the cultivars available are 'Purity White'--12"; 'Snowflake'-- 10". |
| Iris kaempferi
Japanese Iris |
red-purple | 24-30" | summer | few | border | division in spring or fall | Performance: Woodland iris adapts well
to partial shade, full sun, and moist, organic-rich soil that is acidic.
Comments: Cultivars are truly magnificent, and very large flowers should be removed as they fade. There are singles, doubles, and peony-style flowers. They bloom a month later than tall bearded iris. |
| Kniphofia uvaria
Red Hot Poker |
orange, red | 3-4' | late spring | few | border, cut | seed, division | Performance: Requires a well-drained soil. One clump will produce
a large number of blooms. The sword-like foliage stays attractive after
the bloom period.
Comments: For best germination the seed should be prechilled at 40°F for 6 weeks. Plants are sometimes winterkilled because water freezes in the crown of the plant. Several cultivars are available. |
| Lavandula angustifolia,
Lavandula x intermedia Lavender |
blue | 12-14" | summer | few | edging, border, cut flowers and foliage | seed, cuttings | Performance: Short-lived perennial in
this area; heavy soils promote root rot and loss of the plants.
Comments: Desirable for the fragrance of the foliage and flowers. Many cultivars are available, but none has proved more tolerant of Kentucky soil and weather conditions. |
| Leucanthemum x superbum
Shasta Daisy
(Formerly Chrysanthemum x superbum) |
white | 1-3' | early spring | aphids | border, cut | seed, division | Performance: It seems to die for no apparent
reason or can become a weedy pest. Must have a well-drained soil. Divide
every 2-3 years.
Comments: They generally do not bloom the first season from seed. Also listed as C. maximum. 'Alaska' appears to be hardier than the species. |
| Liatris pycnostachya
Cattail Gayfeather, Kansas Gayfeather |
rose-purple | 3-5' | summer | few | border | seed, division | Performance: Requires staking; otherwise,
heavy flower spikes fall over and growing end of spike twists upward. Does
not tolerate wet feet in winter. Indigenous to prairies and woodlands.
Comments: Cultivars 'Alba' and 'Alexander' get high marks for performance. Erect pubescent stems are very leafy. Flower spike may be 15" to 18" long. |
| Liatris spicata
Gayfeather |
purple | 1-2' | early summer | crown rot | border, cut | seed, division | Performance: Indigenous to damp meadows,
savannas, and stream banks. Must have a well-drained location. Removing
the declining blooms sometimes promotes a re-bloom, but the second blooms
are very small.
Comments: Cultivars of L. spicata are not as tall as other species of Liatris. The spike blooms are excellent cut flowers. Spike flowers bloom from the top down. 'Kobold' grows 2' tall and is known as a dwarf cultivar; 'Alba' has white flowers; 'Floristan Violet' has mauve-purple flowers; 'Floristan White' flowers are creamy white. All these cultivars are recommended for hardiness and survivability after wet winters. |
| Liatris squarrulosa
Blazing Star |
violet-purple | 5' | late summer | few | mixed border, cut | seed, tuberous roots | Comments: Definite architectural interest. Highly desired in flower arranging. |
| Limonium tataricum
German Statice (syn. Goniolimon tataricum) |
white, red/white | 1-2' | summer | few | border, cut, dried | seed, division | Performance: This plant does not tolerate
a wet location. It does not like to be disturbed once it is established.
Comments: This plant is grown for the effect of the calyx rather than the actual flower. The blooms drop very quickly, but the calyx persists on the plant for most of the summer. The airy stems are a good substitute for baby's breath. L. latifolium is a related species that is also useful in the garden. It is commonly called Sea Lavender. 'Violetta' is considered an excellent cultivar. |
| Macleaya cordata
Plume Poppy |
white | 6-10' | summer | few | border, mass planting | division | Performance: Plume poppy is a large,
showy plant, but it spreads like crazy. Because it is difficult to contain,
careful thought should be given before this plant is added to the garden.
May be best used in a wild area such as a roadside.
Comments: Also known as Bocconia cordata. Tolerates shade. |
| Malva alcea 'Fastigiata'
Hollyhock Mallow |
pink | 3-4' | summer | mites, Japanese beetles | border | seed, division, cuttings in spring | Performance: This plant blooms for an
extended period. Blooms are 2" in diameter. Prefers a well-drained soil.
Blooms well the first season.
Comments: This plant is often a short-lived perennial, but it reseeds readily. Because of self-sowing, this plant may become a problem in the garden. |
| Oenothera missouriensis
Sundrops, Evening Primrose |
lemon-yellow | 10" | early summer | few | border | seed, division after flowering | Performance: Not particular about soil
but does not tolerate a wet location during the winter.
Comments: Blooms may reach a diameter of 4". Plants may spread 2' in diameter. Single blooms open only in the morning. |
| Paeonia (hybrids)
Chinese Peony |
pink, white, red | 3-4' | late spring | botrytis, thrips, leaf spots, root rots, Japanese beetles | border, cut | division | Performance: It is important not to plant
the crown of the plant too deeply. The "eyes" or buds should be just below
the soil surface. If planted too deeply, the plant won't bloom. There are
many pest and disease problems associated with Paeonia, but the
plant is worth putting in the garden.
Comments: There are several flower forms available and many cultivars to choose from. After the plants bloom, the shrub-like habit of the plant remains attractive in the garden. |
| Papaver orientalis
Oriental Poppy |
red, pink, white | 1-2' | late spring | few | border, cut | root cuttings, division, seed | Performance: Plant grown from seed generally
blooms the second year. If the plants are divided, it takes a while for
them to recover. Once established, the plant does not tolerate disturbance
well.
Comments: The blooms are very showy, but keep in mind that after bloom the foliage will die back and that spot in the garden will be bare. |
| Perovskia atriplicifolia
Russian Sage |
blue | 4-6' | summer | few | border | seed, cuttings, division | Performance: If the foliage is left over
the winter, it should be cut back in the spring. It can be rather rank in
appearance. It grows like a small shrub.
Comments: The gray-white foliage and the long period of bloom make this plant desirable. Like the ornamental grasses, the foliage can add winter accent to the garden. |
| Phlox paniculata
Summer Phlox |
white, pink, blue, red | 2-6' | summer | powdery mildew | border, cut | seed, division | Performance: Declining blooms should
be removed to prevent reseeding. Cultivars that are allowed to reseed produce
inferior plants that, because of their vigor, can literally "run" the desirable
plants out of the garden.
Comments: Many named cultivars are available, offering a range of very attractive colors. Many cultivars are fragrant. |
| Phlox subulata
Moss Pink |
blue, white, pink | 3-6" | early spring | few | border, rock garden, edging | division | Performance: The plant benefits from
light pruning after it blooms.
Comments: Many cultivars are available. The leaves are evergreen and can be useful as a ground cover. |
| Platycodon grandiflorus
Balloonflower |
blue, pink, white | 1-2' | late summer | few | border, cut | seed, division | Performance: Prefers a moist, well-drained
soil. Tall cultivars require staking. Comes up late in the spring. It is
slow growing and does not require frequent division. Some sources say this
plant is difficult to divide.
Comments: The flower buds resemble tiny balloons that open into star-shaped blooms. |
| Polygonum affine
Himalayan Fleeceflower |
rose-red | 6" | mid- to late summer | few | border, ground cover | seed, division | Performance: Prefers a moist soil. Usually
not invasive.
Comments: Best used as a ground cover. New and old flower spikes stay on the plant at the same time and give good contrast. The leaves turn bronze in the fall. |
| Pulsatilla vulgaris (Anemone pulsatilla)
Pasque Flower |
blue | 10-12" | early spring | few | border | seed, division, root cuttings | Performance: Generally performs well.
Comments: These plants probably are still listed in most catalogs as Anemone pulsatilla. The seed heads that appear after bloom can be as attractive as the blooms. |
| Rudbeckia fulgida
Black-eyed Susan, Gloriosa Daisy |
yellow | 2-3' | summer | powdery mildew | border, cut, meadow | seed, division | Performance: Plants can produce large
clumps. Generally performs well. Considered a short-lived perennial, and
some cultivars may last only one season. Generally not as affected by powdery
mildew as other Rudbeckias.
Comments: 'Goldstrum' is an excellent cultivar, but it should be propagated only from cuttings. |
| Rudbeckia laciniata
Cutleaf Coneflower |
yellow | 3-6' | summer | few | border | seed, division, cuttings | Performance: Prefers a moist soil. Requires
division every 3-4 years.
Comments: Cultivars must be propagated by cuttings. 'Gold Drop'--2-3' tall, golden yellow; 'Golden Glow'--3-5' tall, lemon yellow; 'Goldquelle-- 3' tall, gold. Generally thought of as a wildflower. |
| Salvia x superba 'East Friesland'
Meadow Sage |
violet, pink | 18" | late spring | few | border | cuttings, division | Performance: Prefers a well-drained soil.
Tolerates drought conditions. Divide every 1-2 years.
Comments: 'East Friesland' is a hybrid and is also known as 'Ostfriesland'. Other possible cultivars are 'Blue Queen'--18-24" tall, violet; 'Lubeca'--30" tall, violet-blue; 'Rose Queen'--30" tall, rose-pink. |
| Santolina chamaecyparissus
Lavender Cotton |
yellow | 1-2' | summer | few | border, edging | cuttings | Performance: Shearing or pruning the
plant after bloom is beneficial.
Comments: This plant and S. virens, which has needle-like dark green foliage, are both considered aromatic herbs. The foliage of both has a strong odor and was used as a moth repellent. The blooms are button-shaped. Although the blooms are attractive, the plant is really grown for the gray-green foliage. |
| Saponaria ocymoides
Soapwort |
pink | 6-9" | late spring | few | border, edging, rock garden | seed, division, cuttings | Performance: Must have a well-drained
soil. Prune after flowering to promote new growth. May burn out during hot
summers.
Comments: The plant is very attractive used as an edging plant. The common name comes from the plant's use as a source of "soap." |
| Sedum (various species and hybrids)
Stonecrop |
yellow | 3-8" | summer | few | edging, ground cover | division, seed | Performance: This is generally a quick-growing
ground cover that is semi-evergreen. It grows just about anywhere, except
wet areas. Drought tolerant.
Comments: This is a varied group of plants grown mostly for the effect of the foliage. The texture and color are varied, and some do produce blooms. The foliage burns back in a cold winter. 'Dragon's Blood'--foliage is purplish bronze, flowers are dark red. |
| Sedum spectabile
Showy Sedum |
pink, red, white, lilac | 12-18" | fall | few | border, edging, cut, dried | division, cuttings | Performance: The foliage dies back after
bloom, but the new growth begins to emerge in late fall. Does not tolerate
a wet location.
Comments: Sedum x 'Autumn Joy' is a desirable red type. The foliage is succulent in texture, and the plants are uniform and mounded in habit. They would be attractive even if they did not produce blooms. Variegated forms are also available. |
| Solidago hybrids
Goldenrod |
yellow | 2½-6' | late summer | few | border, cut | cuttings, seed | Performance: While often considered a
nuisance plant even though it is the Kentucky state flower, this plant has
new hybrids that are excellent additions to the garden.
Comments: Goldenrod does not cause hay fever (ragweed, which blooms at the same time, is the real culprit). Cultivars developed in Europe are quite nice in the garden. 'Baby Gold', 'Fireworks', and 'Golden Baby' are just a few of these highly satisfactory plants. |
| Stachys byzantina
Lamb's Ears |
purple | 1-2' | late spring | crown rot | edging, ground cover | division | Performance: Tolerates semi-shade. The
plants should be divided every few years to reduce crowding. Hot, humid
conditions promote disease problems that often result in dead patches. The
plant generally starts to recover in the fall.
Comments: The plants are generally grown for the effect of the foliage. The bloom spikes are not showy or attractive. They should be removed after bloom or before to maintain the vigor of the plants. 'Silver Carpet' does not produce flowers. |
| Teucrium chamaedrys
Germander |
purple | 6-10" | summer | few | edging, ground cover | division, cuttings | Performance: This plant tolerates shearing
or pruning into a hedge form. The foliage is evergreen.
Comments: Grown more for the glossy foliage than for the flowers. |
| Tradescantia x andersoniana (syn. T. virginana)
Spiderwort |
shades of pink, white, blue, purple | 1½-2½' | summer | few | border | division, cuttings | Performance: Although each flower is
only open for a day, numerous buds are produced, and the bloom display can
last for 6-8 weeks. Divide every 2-3 years to rejuvenate the clump.
Comments: Foliage may become unsightly after bloom and can be cut back. |
| Verbena bonariensis
Brazilian Verbena |
lavender | 3-4' | summer to frost | powdery mildew | back-ground, grouping, middle of border | root cuttings, seed (erratic germination over 3-5 weeks) | Performance: Excellent plant for stressful
Kentucky summers. If over-fertilized, grows to 4' and must be cut back.
Comments: Named for city of Buenos Aires, where first discovered. Has naturalized in U.S. Panicle of flowers measures 2" across. Zone 7-9 plant; therefore a tender perennial, but it comes back reliably from seed. |
| Verbena 'Homestead Purple' | dark purple | 8" | summer | few | edging, border | cuttings | Performance: Vigorous grower that does
not mind heat. Dark green foliage stays attractive all summer.
Comments: Discovered by Allen Armitage and Michael Dirr at an old homestead. Late to emerge in spring. Best to provide some winter protection. |
| Verbena rigida
Rigid Verbena |
silver-blue | 1' | summer | few | border, edging | seed | Performance: Vigorous grower, dense plant
produces many flowers.
Comments: Zone 7-9 perennial but comes back reliably in Kentucky's hardiness zone 6. |
| Veronica incana
Woolly Speedwell |
blue, pink | 1-2' | summer | few | border, edging, rock garden | seed, division, cuttings | Performance: Does not tolerate a wet
location. During rainy periods the foliage traps water that may cause disease
problems.
Comments: The silver-gray foliage is attractive most of the season. 'Saraband'--18" tall, violet-blue; 'Barcarolle'--12" tall, pink; 'Minuet'--24" tall, pale pink. Cultivar foliage is not as gray. |
| Yucca filamentosa
Adam's Needle |
white | 2-3' | summer | few | border, specimen plant | seed, offsets | Performance: Prefers a light, textured
soil with good drainage. Is drought tolerant.
Comments: Plants from seed require 4-5 years before bloom is produced. Offsets are rooted like cuttings. |