Department of Horticultural Science
Horticulture Information Leaflet 8632
Revised
6/99
— Author Reviewed
6/99
Distributed in furtherance
of the Acts of Congress
of May 8 and June 30, 1914.
Employment and program
opportunities are offered to
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Carolina State University,
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NC
SUMMER AND FALL FLOWERING BULBS
FOR THE LANDSCAPE
A. A. De Hertogh, Professor
M. A. (Kim) Powell, Extension Horticultural Specialist
Summer and fall flowering bulbs provide
another dimension to gardening. They add
beauty and interest to the landscape and,
since most of them are tender, they offer a
unique challenge to the gardener. There are
a large number of different types of bulbs,
offering variations in forms, fragrances,
colors, and lasting brilliance which many
summer annuals cannot achieve.
When choosing “bulbs,” one must always
be aware of a few basic terms. Not all grow
from true bulbs; some grow from rhizomes
(Canna), conns (Gladiolus), or tuberous-
roots (Dahlia). Botanically, there is a
difference, but this is generally important
only to the scientist. The everyday usage of
the term “bulb” includes all plants that grow
from fleshy underground storage organs.
The most important difference which must
be understood is the distinction between
hardy and tender bulbs. In North Carolina,
hardy bulbs (daffodils, hyacinths, tulips,
lilies) over-winter in the ground, while
most tender bulbs (Gladiolius, caladiums,
tuberous begonias) are either dug after the
first frost or the containers are brought
indoors. They are dried or placed in
storage materials in either a warm or cool
place (see Table 1). In the spring, they are
either replanted after the last frost or
subsequently placed outside on patios,
decks, etc.
When landscaping with summer and fall
flowering bulbs, special attention must be
given to the design. As with most annual
flower beds, they are planted in late spring
and usually renovated every year. During
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the winter months, a mulch is spread over
the bare ground. Design the area to
incorporate woody ornamentals which
offer a landscape interest when the bulbs
are not flowering. Favorite uses of these
bulbs are in: borders, ground covers,
rock gardens, and especially in containers
and hanging baskets. Most summer
flowering bulbs are not suggested for
“perennializing” because they do not
overwinter and they are considered
somewhat “formal.” Rhizomous Iris,
Lilies, and daylilies are notable
exceptions. The following are examples
of the eight of the most popular summer
and fall flowering bulbs and their cultural
and storage requirements:
Caladiums are tropical plants with heart-
shaped leaves ranging in size from 6 to 12
inches. The numerous cultivars offer
foliage colors in red, salmon, rose, white,
or green with many variegated
combinations. Caladiums prefer a rich
soil and shade. Grown mostly for their
interesting foliage display, caladiums
perform well in garden borders and
containers. Fertilize them once a month
with 8-8-8 (2 lbs/100 ft2). Caladiums do
not overwinter in N.C. Therefore, they
must be dug in the fall and stored dry at 70
to 75 °F. The tubers are replanted in the
spring after the last chance of frost. One
additional note: most cultivars are
adapted to full shade, but many selections
tolerate partial sun or early morning
sunlight. Full sun generally reduces the
intensity of the foliage color of most
cultivars.