University of Vermont Extension
Department of Plant and Soil Science


Summer flowering bulbs                  OH 44

Leonard Perry, Extension Professor

The addition of summer-flowering bulbs to the home landscape adds not only beauty but interest. These plants have a
particular form as well as brilliant, clear colors. They are easy to grow and can be saved and planted year after year.
They can be planted directly in beds or may be grown in containers. Because there are a number of different types of
summer bulbs, a wide choice is possible.

TUBEROUS BEGONIAS are available in beautiful colors of red, pink, orange, salmon, yellow, or white flowers
attaining a size of 12 to 14 inches in diameter. The tubers can be planted in flats or pots in March or April to get a
faster start, or they can be planted directly in the garden about mid-May.

If starting them early, use shallow flats or pots that have been filled with coarse peat moss. Press the tuber into the peat
moss 3 to 4 inches apart with the concave side up. Place the flats or pots in a dark room, such as the basement, at 65
to 70 degrees F. As the pink shoots start to develop, add more peat moss so it covers the tubers and move them to a
sunny window. Keep the peat moss moist, but do not overwater the tubers because they rot very easily. Fertilize the
young plants with a liquid fertilizer every 2 weeks, according to the rate on the container.

About the middle of May, plants as well as unsprouted tubers can be planted in the garden. Select an area that is well
drained and partially shaded. Set the tubers in the ground just so they are covered and no deeper, because they are
subject to rotting. To allow for plenty of growing space and air circulation, set the tubers or plants 18 to 24 inches
apart. It may be necessary to stake the young plants because many of the larger growing varieties become top heavy in
bloom.

Apply a fertilizer, such as 4-16-16, 5-10-5, 5-10-10, or 5-20-20, at the rate of 3 to 4 pounds per 100 square feet at
monthly intervals. Water when the soil starts to dry--preferably in the morning or early afternoon. This allows the
foliage and flowers to dry before nightfall and reduces chances of disease.

After the frost has killed the foliage, the tubers must be dug, the foliage removed, and the tubers dried for a few days.
Store in peat moss or sawdust in boxes or other containers, but not plastic bags. Place in a storage space that is dry
and where the temperature is maintained around 50 degrees F. Do not allow the tubers to freeze.

The CANNA, years ago, was commonly used where a tall plant with bright red color was needed. This plant had
luxurious green foliage to support the flower. However, the plant seemed to diminish in popularity but has begun a
revival due to new cultivars that offer not only red flowers but pink, orange, yellow, and cream. Also, some have
foliage that is red or bronze, which adds to their appeal. Some cultivars are quite tall reaching a height of 7 to 8 feet
while others are a maximum of 18 inches.

The rhizomes (underground stems) may be started early, such as with begonias, or they can be planted directly in the
garden. Most frequently they are planted directly in the garden about the middle of May. Select a spot that is well
drained and receives full sunlight. The rhizomes should be planted a couple of inches below the surface and 18 to 24
inches apart. Water thoroughly after planting and begin fertilizing as soon as the shoots come through the ground. Use
a dry complete fertilizer, such as 4-16-16, 5-10-5, 5-10-10, or 5-20-20, at the rate of 3 to 4 pounds per 100 square
feet. Apply once a month during the growing season and water thoroughly after application. Water the plants when the
soil begins to dry, and stake if necessary.

Once the foliage has been killed by frost, the dead tops should be removed and the rhizomes dug, being careful not to
damage them. Remove the soil and let the rhizomes lay out on the garage or basement floor for a few days to dry.
Then store them in dry peat moss or sawdust using boxes, bushel baskets, burlap, or feed sacks. Select a spot in the
basement or where they will be dry and can be kept at 45 to 50 degrees F. Do not allow them to freeze.

GLADIOLUS are grown for their magnificent flowers, which come in all colors. There are large flower types as well
as small. hey can be used as background plants in the garden or as cut flowers for inside the home. If care is given to a
planting schedule, flowers can be available from early summer until frost. Therefore, it is advisable to separate the
corms into various planting dates so flowering can be spread out.

The first corms can be planted as early as May 1. Set the corms 4 to 5 inches deep and 5 to 6 inches apart. If they are
grown in rows, allow 36 inches between the rows. In 2 weeks, plant the next group of corms and continue this
procedure until the last of July. By so planting, flowers will be available at almost anytime during the summer. As soon
as the plants are 6 to 8 inches tall, apply a complete dry fertilizer, such as 4-16-16, 5-10-5, 5-10-10, or 5-20-20, at
the rate of 3-4 pounds per 100 square feet. This is the only fertilizer that will be needed during the growing season.
Water the plants thoroughly when the soil starts to get dry.

After the foliage has dried in late summer or autumn, dig the corms, remove the soil, and snap off the dead tops. The
old corm or "mummy" may also be removed at this time, if still present. Spread the corms out on the garage or
basement floor and allow to dry for 3 or 4 days. Place the corms in boxes with dry peat moss or sawdust. If a large
number of corms are involved, make some boxes that are 3 to 4 inches deep with bottoms made of hardware cloth.
Store the corms in a dry, cool place at a temperature of 35 to 40 degrees F. Check them periodically during the winter
for signs of rotting or rodents.

(Adapted from James L. Caldwell, The Ohio State University)


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Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. Lawrence Forcier, Director, UVM Extension System, Burlington, Vermont. University of Vermont Extension System and U.S. Department of Agriculture cooperating, offer education and employment to everyone, without regard to race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status.

Last reviewed 2003