During the long Kentucky summer, a
low maintenance annual flower must:
1) Be thoroughly adapted to and not simply tolerant of hot, dry conditions.
2) Demonstrate insect and disease resistance during weather conditions
that promote them.
3) Require no maintenance labor to prune or remove flower blossoms.
4) Display consistent color and plant size all summer until frost.
5) Be uniform when grown from seed and cuttings and be available from
retailers of plant materials. A broad range of color choices is also desirable.
By choosing a combination of these plants, you should be able to have a
maintenance-free flower garden filled with color (see Table 1 ).
Selected Cultivars
Vinca, Periwinkle (Catharanthus roseus)
The glossy dark green foliage contrasts
nicely with the profuse lavender, pink or white flowers. Plants are very
consistent and form an outstanding ground cover. They are also quite attractive
in planters and other containers.
Vinca is a warm season annual and although
it continues to bloom and produce an effective display until frost, the
bloom size and number may decrease in early fall.
Creeping Habit (4-6 inches tall)
• Polka Dot
• Carpet Series -- Dawn, Pink, Snow,
Magic
Dwarf Habit (8-10 inches tall)
• Little Series -- Blanche, Bright
Eye, Delicata, Pinkie, Linda
• Parasol, Pretty in Pink, Pretty
in Rose, Pretty in White
• Grape Cooler, Peppermint Cooler,
Blush Cooler
• Tropicana Series -- Blush, Bright-Eye,
Pink, Rose
Begonia (Begonia semperflorens x cultorum)
The bedding begonia, commonly referred
to as the wax or fibrous-rooted begonia is one of the most popular bedding
plants throughout the country. Begonias have blooms in shades of pink,
red and white. The diversity of plant habit, leaf form and color (green
and bronze) produce many possible choices for the garden. Begonias that
are well established in the spring withstand drought and heat conditions
in August as well as any other plant.
Begonias are not suitable for home
production. The plants are relatively expensive when compared to other
annuals but the added cost is due to the long production time necessary
in commercial greenhouses.
Most begonia cultivars do well in Kentucky.
The following cultivars meet certain foliage and height criteria.
Bronze Foliage
Dwarf (6-9 inches tall)
• Cocktail Series -- Whiskey, Gin,
Vodka, Rum, Brandy
• Partyflirt, Partyfriend
Tall (10-14 inches tall)
• Danica Series -- Rose, Red
• Othello
• Expresso Series -- Rose, Scarlet,
White
Green Foliage
Dwarf (6-9 inches tall)
• Viva
• Linda
• Olympia Series
• Varsity Series -- Deep Rose, Rose,
Scarlet, White
Tall (10-14 inches tall)
• Partylove
• Hot Tip Series -- Bicolor, Pink,
Red, Rose, Salmon, White
Coleus (Coleus x hybridus)
Coleus are grown for the effect of
the foliage rather than the blooms. All colors of foliage (except purple
and blue) are available from various cultivars that perform well in shade
or semi-shade. The plants are available in diverse plant size, leaf size
and form, and leaf color combinations. Coleus plants are more vigorous
and produce more branches when flowers stems are removed.
Flowers are blue. Foliage colors are
lavender, green, yellow, orange, red, bronze, pink, salmon, and white.
Most cultivars perform well. The following
choices are readily available are:
Dwarf (10-12 inches tall)
• Fairway Series
• Wizard Series
• Jazz Series
Medium (12-18 inches tall)
• Fiji Series (fringed)
• Saber Series
• Carefree Series
Tall (15-30 inches tall)
• Rainbow Series
Impatiens (Impatiens wallerana)
Impatiens, also known as sultana, Busy
Lizzie or bloomin' fool, is well known to all home gardeners. Few plants
can match the number of flowers produced by impatiens. Shady or semi-sun
locations are ideal. Plants in a sunny location may wilt in mid afternoon
but generally recover by early evening. A wide range of bloom colors is
available.
Flowers are lavender, orange, red,
pink, salmon, and white. Foliage is green.
Dwarf (9-12 inches tall)
• Accent Series
• Super Elfin Series
• Futura Series
• Impulse Series
• Novette Series
• Deco Series
• Tempo Series
Semi-dwarf (10-15 inches tall)
• Shady Lady Series
• Gem Series
• Futura Series
• Blitz 2000 Series
Ornamental Peppers (Capsicum annuum)
Ornamental peppers are not as readily
available as they once were. Those available are an excellent choice for
Kentucky gardens. Ornamental peppers grow vigorously throughout the summer
to produce an eye-catching display of bright red and orange fruit from
August until frost. The fruit is edible but extremely hot! These plants
are also effective in containers.
Flowers are purple, lavender, orange,
red, and white. Foliage is purple, green and white.
Tapered Fruit
• Candlelight
• Fips
• Fiesta
Round Fruit
• Holiday Cheer
Blue Salvia, Mealy Cup Sage (Salvia farinacea)
Blue salvia is a maintenance-free,
blue or white flowered annual for full sun locations in Kentucky gardens.
'Victoria' is a particularly good choice producing a bushy, vigorous plant
18-20 inches tall with dark blue flowers and green foliage.
The flowers can be used fresh or dried.
The plants attract a large number of bees, which may be advantageous or
a concern to some home gardeners. The plants may readily self sow, which
could be a future maintenance problem.
( 18-20 inches tall)
• Victoria -- deep blue flowers
• Rhea -- deep blue flowers
• Silver White -- white flowers
(30-36 inches tall)
Blue Bedder -- blue flowers
Creeping Zinnia (Sanvitalia procumbens)
Sanvitalia, known as creeping zinnia,
may be just the answer for an area where a low, creeping, colorful plant
is desired. This plant has an average height of 6 inches and is generally
covered with bright orange daisy-like flowers with a dark center throughout
the gardening season. The plant is generally not available as a spring
bedding plant transplant, yet can be started at home indoors. 'Mandarin
Orange' is a 1986 All America Selection Winner, the foliage is green. 'Double
Sprite Yellow' has bright yellow flowers.
Gomphrena, Globe Amaranth (Gomphrena globosa)
Globe Amaranth is a vigorous, carefree
plant for full sun locations. This plant is adapted to hot, dry garden
sites. The cultivar 'Buddy' produces deep lavender to purple clover-like
blossoms from mid June until frost on very uniform plants.
Globe Amaranth blooms can be used fresh
or dried. Harvest blossoms before they reach peak bloom to retain the best
color. The foliage is green.
(8-12 inches tall)
• Buddy -- violet to purple flowers
• Cissy -- white flowers
(18-24 inches tall)
• Strawberry Fields -- strawberry
red flowers
• QIS Series -- Lilac, Pink, Purple,
Rose, White, Red, Orange
Ornamental Basil (Ocimum basilicum)
The ornamental basils are similar to
culinary basil except that the foliage is deep purple. Plants may be used
in semi-shade, but the best leaf color and plant habit is developed in
full sun locations. White flower spikes are produced at times during the
summer but these are not showy and can be removed to keep the plant bushy
and full.
These plants have the distinct flavor
of green basil and can be used as an herb.
( 18-20 inches tall)
• Dark Opal
• Purple Ruffles -- All America Selections
Winner
• Green Goddess, Purple Goddess
Polka Dot Plant (Hypoestes phyllostachya)
Polka Dot Plant matches its name very
well because it has small dark green leaves spotted with bright pink to
white spots. This plant has been used indoors but for uniform, vigorous
growth it performs best outdoors where it is virtually maintenance-free.
The plants grow 24 to 36 inches tall
and make an excellent annual hedge or a carefree backdrop for other flowering
annuals. It has white flowers.
(24-36 inches tall)
• Pink Splash, White Splash
• Confetti Series -- Burgandy, Red,
Rose, White
Cleome, Spider Flower (Cleome hasslerana)
Cleome or spider flower is one of the
tallest annual flowers that truly thrives under Kentucky' s summer climate.
Spider flower is generally used as a background plant or cutflower. The
large flower spikes with pink and white flowers and pendulous seed pods
are a distinct addition to the flower garden. The flower spikes continue
to get taller throughout the summer and may reach 5 to 7 ft in a full sun
location. Plants may be considered perennial by some gardeners because
the plants reseed readily.
• Queen Series -- Cherry, Pink, Rose,
Violet, White
Dusty Miller (Chrysanthemum ptarmiciflorum, Cineraria maritima,
Senecio cineraria)
Several different genera and species
are referred to as "Dusty Miller." The plants are grown for the effect
of the silvery foliage and may overwinter. Various leaf forms and textures
are available and all can be quite effective as an edging plant or in mass
display.
(8 inches tall)
• Silver Queen -- lacinated silver
white foliage
• Snow Storm
(12 inches tall)
• Silverdust -- finely divided foliage
Melampodium (Melampodium paludosum)
The bushy, well branched plants produce
yellow, daisy-like flowers on green foliage all summer long. They are heat
tolerant with no apparent disease or pest problems. The plants may self
sow.
( 18-24 inches tall)
• Medallion
• Showstar
Abelmoschus (Abelmoschus moscheutos)
The plants are 15 to 20 inches tall
and produce red or pink blooms on green foliage. The plants are closely
related to the Hibiscus and have similar blooms. Each bloom only lasts
one day but the plants produce numerous flower buds. They do best in full
sun and may self sow.
• Pacific Series -- Scarlet, Pink
Table 1. Planting and Color Information for Low Maintenance Annual
Flowers
|
Spacing
(in.) |
Ht
(in.) |
Sun
|
Exposure
|
|
Semi-Shade
|
Shade
|
| Wax Begonia, Bedding Begonia |
12 |
6-14 |
X
|
X
|
X
|
| Vinca, Madagasgar Periwinkle |
12 |
4-12 |
X
|
|
|
| Impatiens, Sultana, Busy Lizzy |
12-18 |
8-18 |
|
X
|
X
|
| Coleus |
12-24 |
10-30 |
X
|
X
|
X
|
| Ornamental Pepper |
10-12 |
10-14 |
X
|
|
|
| Blue Salvia |
12-18 |
18-24 |
X
|
|
|
| Creeping Zinnia |
10-12 |
6-8 |
X
|
|
|
| 'Buddy' Globe Amaranth |
12 |
24 |
X
|
|
|
| 'Dark Opal' Ornamental Basil |
12-18 |
20-24 |
X
|
X
|
|
| Polka Dot Plant |
18 |
24-36 |
X
|
X
|
|
| Cleome, Spider Flower |
24-36 |
36-60 |
X
|
|
|
| Dusty Miller |
10-12 |
8-14 |
X
|
|
|
| Melampodium |
12-14 |
18-24 |
X
|
|
|
| Abelmoschus |
10-12 |
15-20 |
X
|
|
|
Propagation
All recommended cultivars of these
preferred annual flowers are propagated from seed. Unfortunately, begonia,
vinca and impatiens seed are difficult to germinate. Seed of all others
could be germinated by a home gardener with little difficulty (see Cooperative
Extension publication H0-56, Starting Plants from Seed at Home).
Soil
Typical garden soils are adequate for
growing these selected plants. Garden soils that are amended annually with
organic matter provide good water drainage and aeration and retain adequate
moisture and nutrients. Adding organic matter from any source ( e.g. straw,
rotted leaves or manure, grass clippings, peat moss, etc.) is the best
way to assure a beautiful display from your plants.
Be sure to choose a well-drained garden
site. If you must use a low area for your garden, build a raised bed to
be sure drainage is adequate. Add extra organic matter to gardens in shady
locations since these areas tend to dry more slowly than do sunny locations.
Begonias, impatiens and coleus prefer organic soils when grown in the shade.
Patio containers, window boxes and
pots should always allow water to drain. Use growing media in your containers;
garden soil is NOT recommended. The best growing media for these plants
are the professionally prepared, packaged media (e.g. Pro-Mix®, Peters®
Potting Soil, Metro-Mix®, Ball Growing Mix®, etc.) used by greenhouses
for plant production. A satisfactory home-made growing medium is 1 part
sterile garden soil, 1 or 2 parts of sphagnum moss peat, black (Michigan)
peat or compost, and 1 part perlite or coarse sand.
Water and Fertilizer
The selected plants were chosen partly
because no special water or fertilizer applications are generally necessary.
They will show maximum growth if you follow these steps:
1. Plants need about 1 inch of water per week. If rain does not supply
enough water, apply the necessary water in one application, preferably
before 7 p.m.
2. Plants growing in containers need water every 2 to 4 days throughout
the summer.
3. Water new transplants with a complete water-soluble fertilizer (e.g.
20-20-20) shortly after transplanting.
4. Granular, dry fertilizer can be added to the garden when it is tilled
in the spring. Use about 1 lb of 15-15-15 (nitrogen -- potassium -- phosphorus)
fertilizer/100 sq ft of garden or 11/2 lb of 10-10-10 or 3 lb of 5-10-5
fertilizer/100 sq ft. Begonias and vinca are light feeders, so for them,
use half these rates or less.
5. Dry fertilizer or water soluble fertilizer applied in early August
stimulates late summer growth. Apply dry fertilizer between the plants,
scratch it into the soil and water the garden thoroughly. Use dry fertilizer
at half the rates described above. Water-soluble fertilizers are easiest
to use for container plants. Apply them according to the label recommendation.
Pests
Most of Kentucky's common insects and
diseases do not harm these plants. However, plants purchased with insects
problems will probably continue to have these problems. Spider mites and
mealybugs, brought into your garden on plants, can damage impatiens, coleus
and vinca. Also, blue salvia could be purchased with a whitefly problem.
Disease problems on the leaves of these
plants are nearly nonexistent. However, root and stem rotting organisms
kill plants when soil drainage is inadequate.
Weeds present little problem since
these plants grow vigorously enough to out-compete most weeds. If hand
weeding is not feasible, these plants grow well with organic or plastic
mulches or when recommended herbicides are used correctly.
About the Authors
Bob Anderson has worked with commercial
flower growers in Kentucky for 17 years. His special interests include
house plants, annual and perennial flowers, and he directs research on
mechanized production of cutflowers. He edits the monthly, Kentucky Hints
and Facts, for commercial greenhouse operators and is actively involved
with the University of Kentucky Arboretum.
Sharon Bale has been an Extension Floriculture
Specialist since 1975. She works with home horticulture, especially annuals
and perennial flowers, herbs and floral design. For at least 12 years she
has been an All-America Selection judge, helping to select which new flower
cultivars win national acclaim as All America Selections.
Trade names are used solely for identification.
No product endorsement is implied, nor is discrimination intended, to the
exclusion of comparable products.