After weeks of unusually cold nights (think freezing temperatures!), finally planted my dahlia tubers last weekend, which is later than I would normally aim for. If you are somewhere in the northern hemisphere reading this and feeling behind on getting your summer garden going, I want you to know: you are not too late! Most of us still have a full season ahead. And for readers in the southern hemisphere, save this for your spring planting in a few months.

I have grown dahlias for seven years now, in raised beds and grow bags in my front yard garden. I grow them for fresh arrangements, pressed flower art, silica drying, and weekly cuts I send to a local floral designer and wedding cake pastry chef. This is the version of growing them I have landed on, after losing my first batch to rot and learning some things the hard way.

I order from Swan Island Dahlias in Oregon every year. They are a family-owned farm that has been around for 90 years. The prices are reasonable, the selection is gorgeous, and every tuber comes stamped with the variety name. Their plastic markers also list bloom size, color, and height, which is hugely useful when you are planning your bed.

I used to save and divide my own tubers at the end of the season. I stopped, because dividing tubers in the fall is a full-time job on top of an already full-time business. Now I leave them in the ground to rot over winter (they add organic matter back to the soil) and buy fresh in spring. If you fall in love with a specific variety, by all means dig and divide that one. Otherwise, give yourself permission to start fresh each year.

People ask me which dahlias I recommend, and the honest answer is I grow new ones every year because I am curious. I do have a few rules though:

For vase life, pom pom varieties last up to a week. Dinner plate and decorative types are more like 5 days, max.

Spacing. Standard advice is 12 inches apart. I plant mine closer, more like 8 to 10 inches. The plants fill in and support each other, and I get more flowers per square foot. 

Drainage matters more than anything. My first year, I planted tubers in a spot with clay soil and poor drainage. I lost about half of them to rot. Dahlias hate wet feet. If you have heavy clay or a low spot in your yard, plant them in a raised bed or grow bag, or amend the soil heavily with compost.

Sprinkle bone meal in the hole before placing the tuber. Dig a hole about 6 inches deep. I use Burpee Organic Bone Meal. Bone meal is rich in phosphorus, which is the nutrient dahlias rely on for strong root development and abundant blooms. A small handful in the bottom of each hole gives the new roots something to grow into. I also mix in a little all-purpose fertilizer.

Lay the tuber horizontally with the eye (the little sprout point) facing up. Cover with soil and do not water yet. Tubers rot easily when they are sitting in damp soil before they have started growing.

You can grow dahlias from seed, but you have to start them indoors in February or early March. By May, it is too late. Stick with tubers.

Once your plants are about 6 inches tall, pinch the central growing tip just above a leaf node. This signals the plant to branch out from below, giving you a bushier, fuller plant with more flowers. It feels counterintuitive to cut a healthy plant, but it is the single biggest thing you can do for your yield.

Staking goes in early. Dahlias get heavy as the season progresses, and a plant that flops in July is much harder to rescue than one that has been growing through a support since June. I use modular square tomato cages from Amazon, which I can connect into larger frames as the plants grow.

Dahlias are heavy feeders and heavy drinkers. Water deeply, especially once they are blooming. A dahlia that is hungry or thirsty will give you smaller flowers and shorter stems.

In Oak Park, my big three are rabbits, Japanese beetles, and earwigs. (Slugs are not a problem in my garden, but I sprinkle organic slug pellets anyway because they help with earwigs too.)

Rabbits will mow down a young dahlia overnight. I cover each shoot with an adjustable plastic plant guard the moment it pokes through the soil. These are the ribbed cages sold for protecting tree saplings, and they are adjustable so you can connect them for larger areas. Just keep in mind that the wider the protected area, the easier it is for a rabbit to hop inside. For taller shoots, I stack two guards vertically instead. Once the plant has multiple sets of leaves and is taller than a rabbit can comfortably reach, I remove them.

Japanese beetles arrive in July and they are destructive. I walk the bed twice a day in beetle season and hand-pick them into soapy water. For buds I really want to protect (especially for designer commissions or wedding work), I slip an organza bag over the bud and cinch the drawstring. The bloom opens inside the bag, fully protected.

Dahlias do not continue opening after you cut them. Whatever stage the bloom is at when you snip it, that is the stage it stays.

For pressing or silica drying: You can harvest smaller, slightly less open blooms for delicate pressed work, or fully open ones for a bigger statement piece. The drying process locks in whatever stage you cut at.

For the vase: Harvest when the flower is about 80% open, with the center still tight and firm to the touch. A soft center means the flower is past its peak.

Always harvest in the cool hours: Early morning after the dew has dried, or early evening. Never midday. Heat-stressed flowers wilt fast and do not recover.

Cut deep into the plant. When I started, I made the rookie mistake of cutting just the short stem with the bloom. The plant responded by sending up thin, weak side shoots that gave me sad little flowers on sad little stems. Now I cut at least 12 inches into the plant, always just above a leaf node. The plant branches strongly from that node and rewards me with thicker stems and bigger blooms for the rest of the season.

Of all the flowers I grow, dahlias might be my favorite to press, though they feel intimidating at first. The textures dry beautifully, and one bloom can carry a whole composition.

How you press a dahlia depends on its form. For most varieties, I use a microwave press for a couple of rounds to extract as much moisture as possible, then transfer to a traditional press. Smaller, open-form types like singles and collarettes go straight into the press whole with 3-4 paper changes over 2 weeks. They tend dry flat without much fuss. Decorative, dinner plate, and ball types are too thick to press whole, so I take them apart petal by petal, press the pieces flat, and reassemble the flower when I am composing finished art. Or you can thin out the petals and do two short rounds in the microwave before transferring to a traditional press. 

I am working on a dedicated post about preserving dahlias for pressed art, silica drying, and a few other methods. For now, what I want you to know is that even the most stubborn-looking dinner plate is pressable. You just have to be willing to take it apart first.

Dahlias are prolific bloomers. Once they start, they do not stop until the first frost (around the third week of October here in Chicago). If you don’t have a full garden, shorter varieties do very well in pots and grow bags. Cut regularly and they’ll reward you with dozens of blooms you can preserve and turn into artwork and gifts later.

Are you growing dahlias this year? I would love to hear in the comments.