FLOWER BED: ANNUALS
Ch. 14, pp. 22 - 26
This is a term loosely used to include corms, tubers,
tuberous roots, and rhizomes as well as true bulbs. This section
of the chapter will refer to all of the above as bulbs. However, a
true bulb is a complete or nearly complete miniature of a plant
encased in fleshy modified leaves called scales which contain
reserves of food. Corms are the base of a stem that becomes
swollen and solid with nutrients. It has no fleshy scales. The
tuber, which is an underground stem that stores food, differs from
the true bulb or corm in that it has no covering of dry leaves and
no basal plant from which the roots grow. Usually short, fat and
rounded, it has a knobby surface with growth buds, or eyes, from
which the shoots of the new plant emerge. Tuberous roots are the
only ones from this group that are real roots; their food supply
is kept in root tissue, not in stem or leaf tissue as in other
bulbs. Rhizomes, which are sometimes called rootstocks, are
thickened stems that grow horizontally, weaving their way along or
below the surface of the soil and at intervals sending stems above
ground. Many vegetables are propagated from or produce edible
organs of these types (e.g., tuber, Irish potato; tuberous root,
sweet potato; rhizome, Jerusalem artichoke; bulb, onion).
Bulbs are broadly grouped into spring-flowering
(January-May) and summer-flowering (June-September). Spring bulbs
provide early color before most annuals and perennials. One of the
most popular spring bulbs is tulip. These are sold by type and
variety. Tulips come in all colors except blue. Some of the most
common types are:
||Bronzed, not clear colors
||Petals recurve - bell-shaped
||Twisted, ruffled petals
||2 or more rows of petals
Narcissus, daffodils, and jonquils are classed by
length of corolla in relation to perianth segments. They come in
the colors of white, yellow, red, and peach, but not blue. Many
have naturalized in places. Hyacinths produce a large single spike
of many small, fragrant flowers, and come in a complete color
range. Crocus are usually grown for early bloom (in snow). There
are no red crocuses.
Selecting quality spring bulbs is very important,
because the flower bud has already developed before the bulb is
sold. Size is also important; look for plump, firm bulbs. Select
on a basis of color, and size for intended purposes; for example,
small ones for naturalizing and large ones to stand out as
specimen plants. Keep cool (60 to 65º F.) until planting.
The summer-flowering bulbs include amaryllis, tuberous
begonia, caladium, day lily, dahlia, gladiolus, lily, and spider
Culture and maintenance of bulbs
Storage. If bulbs are bought before planting time, keep
them in a cool, dry place. A temperature of 60 to 65º F. is
cool enough to prevent bulbs from drying out until time for
planting. Temperatures higher than 70º F. will damage the
flower inside spring-flowering bulbs. Rhizomes, tubers, and
tuberous roots are more easily desiccated than bulbs and corms,
and should be stored in peat, perlite, or vermiculite.
Site Selection. In selecting a site for
planting, consider light, temperature, soil texture, and function.
Most bulbs need full sun. Select a planting site that will provide
at least 5 to 6 hours of direct sunlight a day. Bulbs left in the
ground year after year should have 8 to 10 hours of daily sunlight
for good flowering. Bulbs planted in a southern exposure near a
building or wall will bloom earlier than bulbs planted in a
northern exposure. Adequate drainage is an important
consideration. Most bulbs and bulb-like plants will not tolerate
poor drainage, and rot easily if planted in wet areas. Function
must also be kept in mind. If bulbs are being used to naturalize
an area, toss the bulbs then plant them where they fall to create
a scattered effect. Spanish squills will do beautifully along with
daffodils to achieve a natural effect.
Site Preparation. Good drainage is the most
important single factor for successful bulb growing. Bulb beds
should be dug when the soil is fairly dry. Wet soil packs tightly
and retards plant growth. Spade the soil 8 to 12 inches deep. As
you dig, remove large stones and building trash, but turn under
all leaves, grass, stems, roots, and anything else that will
decay. Add fertilizer and organic matter to the soil. Use 1 pound
of 5-10-10 fertilizer for a 5 by 10 foot area, or a small handful
for a cluster of bulbs. Place a 1 to 2 inch layer of organic
matter over the bed. Thoroughly mix the fertilizer and organic
matter with the soil. For individual planting holes, loosen the
soil below the depth the bulb is to be planted. Add fertilizer and
cover with a layer of soil (bulbs should not contact fertilizers
directly). Set bulb upright in planting hole and cover with
amended soil. In wet, hot summers, organic fertilizer can retard
blooming and promote disease, especially among gladiolus not
Time of Planting. Hardy, spring-flowering bulbs
are planted in late summer or early fall. Hardy, fall-flowering
bulbs, such as colchicum, are planted in August. Tender,
summer-flowering bulbs are planted in the spring after danger of
frost. Lilies are best planted in late fall.
Depth of Planting. It is best to check correct
planting depth for each bulb with a successful local grower or
other good local source. Bulb catalog and reference book
recommendations for planting may be either too shallow or too deep
depending on soil condition. As a general rule of thumb, bulbs
should be planted 2 to 3 times the diameter of the bulb in depth.
It is important not to plant bulbs too shallow, as this will
encourage frost heaving.
Watering. Normal rainfall usually provides
enough moisture for bulbs. But during dry weather, water plants at
weekly intervals, soaking the ground thoroughly. Be especially
careful not to neglect bulbs after blooming.
Mulching. In the winter, mulch bulbs 2 to 4
inches deep with organic material such as straw, pine bark, hay,
or ground leaves. Do not use large leaves, as they may mat too
tightly on the ground. A winter mulch prevents alternate freezing
and thawing, which damages bulbs and plant roots. Apply mulch
after cold weather arrives. You may damage the bulbs if you mulch
while soil temperature is still high. Remove mulch as soon as
danger of severe freezing has passed, in early spring. If mulch is
left on the ground after new growth starts, tops of new shoots
will be pale green or colorless, and new stems and foliage may be
Fertilizing. After plants bloom, fertilize them
lightly with 5-10-10 fertilizer. Use no more than 1 pound for a 5
by 10 foot bed. Avoid high-nitrogen fertilizer. Be sure to keep
fertilizer off the leaves and away from roots; it will burn them.
In addition to 5-10-10 fertilizer, you can use bonemeal as an
extra source of phosphorus.
Staking. Some tall, heavy-flowered bulbs may
require staking. Stake plants when they are emerging, but be
careful not to damage the bulb with the stake. For flowers that
face one direction, use the stake to orient the face to the front
of the bed.
Deadheading. When flowers fade, cut them off to
prevent seed formation. Seeds take stored food from the bulbs.
Moving. If leaving bulbs in place for bloom
next year, do not cut the leaves after flowering until they start
to wither. Green leaves produce food for plant growth next year.
After leaves turn yellow, cut and destroy the stems and foliage of
the plants. Dead foliage left on the ground may carry disease to
new growth the next year. If moving bulbs from one place to
another, or if a planting has become crowded and ceased blooming,
move only after the foliage has faded. Bulbs dug and moved before
foliage fades are useless.
Digging and Storing. Many summer-flowering
bulbs should be dug and stored, as they are tender. This is done
when the leaves on the plants turn yellow. Use a spading fork to
lift the bulbs from the ground. Wash off any soil that clings to
the bulbs, except those that are stored in pots or with the soil
around them. Spread the washed bulbs in a shaded place to dry.
When dry, store them away from sunlight in a cool, dry basement,
cellar, garage, or shed at 60 to 65º F. Avoid temperatures
below 50 or above 70º F. Be sure that air circulates around
stored bulbs. Never store bulbs more than two or three layers
deep, as they generate heat and cause decay. Leave the soil on
achimenes, begonia, canna, caladium, dahlia, and ismene bulbs.
Store these bulbs in clumps on a slightly moistened layer of peat
moss or sawdust in a cool place. Rinse, clean, and separate them
just before planting.