Planting Your Tubers:
Most dahlia growers in the Spokane area plant their tubers in the garden the 3rd weekend in May or Memorial Day weekend. Whenever you are comfortable putting out your tomatoes is a general guide on when to plant dahlias. Depending on the varieties and types selected, dahlias may be planted in borders, along fences or walls, in pots, in beds or in rows. Dahlias grow best in full sun, but will tolerate some shade. Try to select a planting area that gets 6 hours of or sun a day. They do best in sandy loam that is slightly acidic but will grow row successfully in any type soil that is well drained. Dahlias should be staked and the stake set before the tuber is planted. A 3-4' stake will suffice for small dahlias but the large flowering type.
Pinching (Topping or Stopping) and Disbudding:
Pinching is the removal of the growing center stem at a certain point in the dahlia plant's development, depending on the size dahlia being grown. Pinching encourages strong side branching, makes a plant more sturdy and produces larger blooms. This prevents a lanky, thin plant that produces only one flower at the growing point.
AA & A Dahlias: Pinch out center stem when 2 or 3 pairs of leayes appear
B Dahlias: Pinch out center stem when 3 or 4 pairs of leaves appear.
Dahlias under 6' in diameter: Pinch out center stem when 4 or 5 pairs of leaves appear.
Miniatures and pompons and other types: Pinch out center stem when 5 or 6 pairs of leaves appear.
Mignon Singles: Do not pinch.
Disbudding is another method to achieve quality blooms. Dahlias send out 3 buds at the flowering terminal, a center bud and 2 side buds. By carefully removing the 2 side buds when they are the size of a pea, the center bloom will grow stranger, larger and have a better stem. It is necessary to remove more than the top 2 side buds for larger blooms.
AA & A Dahlias: Disbud 3 sets of leaves. (Disbud the terminal end and down 2 more sets of leaves)
B Dahlias & Balls: Disbud 2 sets of leaves. (Disbud the terminal end and down 2 more sets of leaves)
BB, Miniature, Miniature ball, Pompons & other types: Just disbud the flowering terminal.
Mignon Singles: Do not disbud.
INLAND EMPIRE DAHLIA SOCIETY
Dahlias are classified according to the shape and arrangement of their petals. Single Flowering dahlias have no more than a few rows of petals and show a central disc. Double flowering dahlias have multiple rows of petals and display no central disc. Double flowering dahlias include formal and informal decorative, cactus and semi-cactus, ball, miniature ball, waterlily, pompon and laciniated types classified by size. Single flowering dahlias include single, anemone, collarette, peony, orchid, orchette and mignon single. The novelty dahlia can be either single or double, depending on the variety.
PICTURES OF DIFFERENT FORMS
Tying
The plant will need to be supported by loosely tying it to the stake. Tying will be necessary throughout the season as the plant continues to grow to avoid breaking or blowing over in the wind and as the plants become top heavy with blooms. Tie with each foot of growth.
Watering & Fertilizing
Dahlias should be watered deeply and often to prevent the soil from drying out. After the plants have established good growth, use water soluble 20-20-20 fertilizer. Start with 2 cups per plant and then go to 1 to 2 quarts per plant at next feeding. A well-blended granular fertilizer can be used. After the first or second week of August, or when the plants start to bloom, use 0-10-10. Nitrogen after this time will cause too much green growth instead of flower and root production. Water the Dahlia bed well, then spray the fertilizer directly over the plant in the cool of the evening. Don't fertilize more than every 2 weeks.
Cultivating
After mid-July, don't cultivate more than an inch deep within 18" of the plant, as dahlias have shallow feeder roots. A mulch can be applied after the soil is warm.
Digging
It is necessary to dig dahlias in the fall in areas where they will freeze. After a killing frost, cut the plants off to about 6" above the ground. After 1 week, dig and wash the tuber clumps. Be sure to transfer the identification tags to the clump and write on each tuber with an indelible pencil after dividing.
Growing Dahlias
Storing Tubers
Tubers can be stored in layers of vermiculite, sawdust or shavings. Some growers even use newspapers and plastic bags. Storing then tubers in plastic bags with vermiculite seems to work well. The storage medium may need to be sprayed lightly with water, but too much moisture will cause rotting. Store them at a cool, even temperature of approximately 40-45 F. If you ask 20 of our members how they store dahlias, you may get 20 different answers. The key is to find what works for you and stick with it. Below is one method several members swear by, the Plastic Wrap Method.
Plastic Wrap Method
For storing your tubers (excerpts from article "No Fuss: Store your tubers in Plastic Wrap" published by Mandella, Mandella & Peters):
Tear off a sheet of plastic wrap about 20 or more inches long and lay it flat on a level surface. Place a tuber on one end and roll the plastic wrap over one complete turn. Lay another alongside and roll again. Be certain that no tuber is touching another; plastic wrap must separate all tubers.
You may wrap up to five tubers or so per package, but in the last 5-7 inches, fold over the side portions of the plastic wrap and continue to roll to completion. Fasten with a piece of masking tape that is labeled with the cultivar's name and any other information. The wrapped tuber bundles should be stored at 40-45 degrees fahrenheit in corrugated boxes or another container that you would ordinarily use. The tubers emerge very firm, and the losses to tuber rot have been in the order of 3-6% per year.
There is essentially no loss from shriveling or drying. When you are ready to plant or pot your tubers, simply open the package, remove the tubers and check for eyes. The tubers tend to eye up earlier with this method, but some will be blind stock with no eyes.
Other methods include packing in cedar shavings or peat moss inside plastic bins. Spritz lightly and check throughout the winter. Tubers may need some added moisture.
Dividing
Dividing of tubers is usually done in the fall, using a sharp knife or pruning shears, leaving a piece of the crown with an eye connected to each tuber. When roots are divided from the clump, each root must have an eye in order to grow next year. Hint: we have dividing demonstrations at our October meeting each year where you can see top local dahlia growers explain how they divide and ask questions.
Classifications of Dahlias
COLORS
BI - Bicolor
BK - Black
BR - Bronze
DB - Dark Blend
DP - Dark Pink
DR - Dark Red
FL - Flame Blend
L - Lavender - (LV)
LB - Light Blend
OR - Orange
PK - Pink
PR - Purple
R - Red
V - Variegated
W - White
Y - Yellow
SIZES
AA - (Giant) over 10" in diameter
A - (Large) 8 to 10" in diameter
B - (Medium) 6 to 8" diameter
BB - (Small) 4 to 6" in diameter
M - (Miniature) up to 4" in diameter
MC - (Micro) under 2" in diameter
BA - (Ball) over 3.5" in diameter
MB - (Miniature Ball) 2 to 3.5" in diameter
P - (Pompon) up to 2" in diameter
S - (Single) over 2" in diameter
ST - (Stellar) over 2" in diameter
MST - (Micro Stellar) up to 2" in diameter
WL - (Waterlily) over 2" in diameter
MWL - (Micro Waterlily) up to 2" in diameter
NX - (Novelty Double) over 2" in diameter
MNX - (Micro Novelty Double) up to 2" in diameter
PE - (Peony) over 2" in diameter
MPE - (Micro Peony) up to 2" in diameter
AN - (Anemone) over 2" in diameter
MAN - (Micro Anemone) up to 2" in diameter
NO - (Novelty Open Center) over 2" in diameter
MNO - (Micro Novelty Open Center) up to 2" in diameter
CO - (Collarette) over 2" in diameter
MCO - (Micro Collarette) up to 2" in diameter
O - (Orchid) over 2" in diameter
MO - (Micro Orchid) up to 2" in diameter
OT - (Orchette) over 2" in diameter
MOT - (Micro Orchette) up to 2" in diameter
S - (Single) over 2" in diameter
MS - (mignon single) up to 2" in diameter
FORMS
AN Anemone-flowering
BA Ball
C Straight Cactus
CO Collarette
FD Formal Decorative
IC Incurved Cactus
ID Informal Decorative
LC Laciniated
MB Miniature Ball
MC Micro
MAN Micro Anemone
MCO Micro Collarette
MNO Micro Novelty Open
MNX Micro Novelty Double
MO Micro Orchid
MOT Micro Orchette
MPE Micro Peony
MST Micro Stellar
MWL Micro Waterlily
MS Mignon Single
NO Novelty - Open (Disc) Center
NX Novelty - Fully Double
O Orchid - flowering
OT Orchette
P Pompon
PE Peony - Over 2" in diameter
S Single
SC Semi-Cactus
ST Stellar
WL Waterlily