Dazzling Dahlias > Dahlias- Garden Basics
Dahlias- Garden Basics

Jan 15, 2008

Planting Dahlias

Don't let the showy appearance fool you - dahlias are easy
to grow. Prepare the soil by digging to a depth of about a
foot and amending with compost if necessary before
planting. Set the tubers 3 to 4 inches deep about 10 days
before the last expected frost. The distance between plants
depends on the variety you are planting. A spacing of about
2 feet will work for most varieties.

Tall varieties and those with huge flowers will require
staking. For easy support, plant dahlias around a trellis
or fence. When planting in a mixed border, it's tempting to
plant them in the back because of their height, but make
sure they are accessible because in zones 7 and colder they
will have to be dug up after the first frost.

Growing Dahlias

Dahlias need full sun and appreciate steady moisture and
regular feedings until the flowers start to appear. At this
time, taller varieties may need to be staked. For a bushier
plant, pinch out the growing shoot after plants have
produced 4 to 6 pairs of good, strong leaves. A number of
buds will appear at the top of the stems. To get maximum
sized flowers, some of these buds should be pinched out. If
only one bud is allowed to develop, the largest possible
flowers will be produced. It takes about 6 weeks from the
time buds are removed until another series of buds is
formed and about three weeks longer for the buds to open.

Dahlias As Cut Flowers

Dahlias are beautiful and long lasting cut flowers, and
cutting encourages to plant to produce more blooms. Cut
fully open flowers early in the morning. Use a sharp knife
to avoid crushing the stems, and then dip the stems in hot
water to seal and remove foliage from the lower part of the
stems below the water level before placing them in the
vase. Leaves will yellow if they don't have enough light,
so set your arrangement in a sunny window. A solution of
1/4 teaspoon of bleach plus 2 teaspoons of sugar to 1/2
gallon of water will prolong the vase life. Cutting the
bottom 2 inches from the stems every other day will help to
keep the flowers looking fresh.

Insects and Diseases

Indications: Aphids will be visible on the foliage. Also
look for curled leaves and a wet, sticky film on foliage.
Treatment: Soap-Shield, yellow sticky traps and ladybugs.

Spider Mites
Indications: Spider mites are tiny and difficult to see.
Look for spotted leaves, bronzing leaves, fine webbing on
foliage and general loss of vigor.
Treatment: Soap-Shield.


Indications: Thirps are very tiny, but sometimes you can
see them on the blossoms. They fly and run rapidly, and are
almost impossible to catch.
Treatment: Soap-Shield and yellow sticky traps.

Dahlias are susceptible to fungal and viral diseases and
bacterial wilts. Light yellow vein banding, wavy yellow
lines and rings or spots of yellow on the leaves are
indications of viral diseases. Other indicators include
stunted growth or abnormally shaped leaves. Once a plant is
infected with these diseases there is nothing you can do
but remove it before the disease spreads and destroy the
plant. Don't compost diseased plants!

Lifting Tubers

If you live in an area where the ground freezes in winter,
you will have to lift your dahlias and store them in cool
but frost-free area over the winter. This usually includes
zones 7 and colder.

When bud production slows and flowers are poorly colored
it's time to cut the plants back. If you grow several types
of dahlias, place a tag around the base of each plant for
identification before cutting. It's best to cut the stems
through a node where it will be solid. If the weather is
dry, let the tubers stay in the ground for a week to ten
days, but lift the tubers as soon as possible if you
suspect rain or a hard freeze.

To lift the tubers, dig into the soil about 8 to 10 inches
away from the stems. Lift gently to pry the roots away from
the soil. When all roots have been loosened, dig under the
tuber and firmly remove it with the ball of soil. Remove
all loose soil, but leave moist soil that clings to the
roots and tubers. Brush off the remaining soil as it dries

Once clean, store the clumps of tubers in a cool area with
good ventilation. The tubers can be placed in dry sand with
the stems exposed. Check them monthly to make sure they
aren't shriveling, which means they are too warm or too
dry. Soft spots should be removed with a sharp knife. To
prevent rot, dust with an organic fungicide.


Start seeds indoors in early spring. The seeds will
germinate a little faster if you use a heating mat, or
place them on top of a refrigerator for heat. Begin to
harden off when night temperatures stay above 50 degrees.
Seedlings will not tolerate frost, so plant them out after
your last expected frost date. Many dahlia seeds available
for purchase are grown as annuals because the tubers
produced by these plants won't result in flowers similar to
the parent plant.

Large tubers can be divided. A tuber won't grow unless it
has an 'eye' or a little sprout growing from it, so make
sure that all your divisions contain at least one eye.

Cuttings taken when the shoots are 3 to 4 inches long are
easily rooted in sandy soil. Use a rooting hormone for best


Frey's Dahlias 12054 Brick Rd. SE, Turner, OR 97392 

Comments or questions? Phone 503.743.3910; Email us at info@freysdahlias.com or click the "Contact Us" link on the Main Menu.

We accept  these major credit cards: 
Credit Card Logos for Your Web Site
Merchant Services
SecurityMetrics Credit Card Safe