Dahlias for your garden!
Thank you for being a returning Garden and Roads Subscriber! In the spring, you received a dahlia tuber as your thank you gift for participating in the 2022 Subscription Group. Dahlias are one of the most widely grown and well-loved cut flowers and add color and interest to any garden. Dahlias can be small enough to grow in a pot or large enough that the blooms are bigger than a dinner plate. Flowering in a rainbow of colors from mid-summer until first fall frost, they produce abundant blooms and tubers. I hope this is the start of your journey growing these amazing flowers
Storing Dahlias for the Winter
We had our first frost, but the ground isn’t yet frozen - that means its time to winterize your dahlias. Here in the Medford area we are in Agricultural Zone 6B. Dahlias are originally from Mexico and Central America and that means your dahlias are unlikely the survive the New England winter. Below are some tips on winterizing your dahlias.
DIG YOUR DAHLIS: Unless your dahlias are in pots where you can just bring them inside to a basement or garage that doesn’t have temps below 30 degrees, you will need to dig up your dahlias and store them in a protected area that won’t freeze. Try to aim for a day when it hasn’t rained in a few days so the soil is drier and easier to work with.
Cut back the stalk to a couple inches high & compost the leaves & cut stalk
Hopefully you’ve labeled your dahlias, so make sure your label is attached to the stem, if you haven’t labeled and you remember what color it was, reference the images below to find out the variety. Now that you know what variety this is, take the time to label your dahlia clump by taping the name on the stem stump. If you don’t label your dahlias, get ready for dahlia surprise next spring!
Using a pitchfork (recommended) or shovel loosen the soil 6-8 inches away from the stalk - proceed gently to navigate around the tubers. Gently shake off dirt or dig it out with your fingers. Try not to break any of the tuber necks.
Clean your tuber clumps - hose them down outside and allow to dry in a shaded spot 4 - 48 hours. Monitor your tubers, you want them dry, but not starting shrivel. Avoid drying them on asphalt or concrete in a sunny location as they will heat up and dry out quickly.
Examine the clumps for any rotten tubers and trim off excess roots and stem. Many people remove the “Mother Tuber which was the one planted in the spring. You can usually identify it as a large one with darker and thicker skin.
If you are choosing to keep your clumps whole for storage, place your tuber clump in a container like a cardboard box or a milk crate lined with craft paper and cover it with wood shavings, peatmoss or vermiculite (I’ve heard some people use sand, but that will make the box very heavy). Store in a cool dark area like a basement or garage
DIVIDE YOUR DAHLIAS: You can divide your dahlias when you dig them in the fall or after you take them out of storage in the spring.
Using clean scissors or a knife cut into the clump keeping the individual tubers (crown, neck & body) together as best you can). If it’s a really big clump, you can divide into quarters or thirds before trying to take off individual tubers
Look for tubers with a small raised bump (eye) on the crown - only these tubers will be viable next year. If you aren’t feeling confident in identifying the eyes, keep all the intact tubers and see what grows next spring
Once you’ve separated your tubers, write the name of the variety on the tuber using a waterproof sharpie or a dahlia pencil ($3)
Put down an initial layer of wood chips, peat moss or vermiculite in a plastic or carboard box.
Place your tubers close, but not touching in a container plastic box, carboard box and cover each layer with your packing material until the box is full - make sure to add a last layer of fill before closing the box.
If you have more than 1 box of tubers, I’d recommend writing an inventory of what’s in the box where you can easily reference it in the spring.
Growing Dahlias
Dahlias require full sun (at least 8 hours daily) to thrive and bloom abundantly. Dahlias are cold-sensitive and should not be planted until the soil has warmed to above 60°F (15°C) and all danger of frost has passed. Check your last frost date prediction in the Farmer’s Almanac.
Dahlias aren’t very picky about the soil, but for best results, amend planting site with several inches of compost or well-rotted manure, a light dusting of bone meal and a balanced organic fertilizer. Mix all ingredients into the soil to distribute evenly.
To plant, dig a hole 4 to 6 inches (10 to 15 cm) deep and place the tuber on its side, horizontally, with the growing eye facing up. Once in place, refill the hole with soil. Dahlias get quite large, so allow at 12+ inch spacing if planting more than one.
Dahlias require consistent water throughout the growing season, but should not be watered until you see the first green shoots poking through the ground; overwatering before shoots are visible can lead to tuber rot. Dahlias perfer a deep soaking every few days to a sprinkle every day.
To encourage branching and longer stems, pinch the growing tip by snipping 3-4 inches (make sure there are at least 3 sets of leaves still on the plant.
By mid-summer, you may need to stake plants to keep them from falling over. Place tall, sturdy post next to tubers at planting time so you can tie stems to them as they grow.
Dahlia Tubers may over-winter in milder climates, but in New England, you will need to pull your tubers out of the ground, pack them in peat moss or vermiculite and store in a cool dark place for the winter. More on digging, dividing & storing tubers from the American Dahlia Society
If you want to learn more and grow more dahlias. consider joining the Yankee Dahlia Society
2023 New Garden and Roads Dahlia Varieties
