How to Care for Cut Dahlias

Dahlias are the big, many-petaled blooms of late summer and fall, from tight little pompons to open, ruffled faces. They are not long-lived cut flowers: with good care most last 4 to 7 days in the vase, and the largest heads are often at their best for the first few of those. The one thing that matters most is water: their stems are hollow and they wilt quickly if they go even a short time without a drink.

When your dahlias arrive

1. Unpack the arrangement right away. If a doorman or an office lobby held the delivery, check the water as soon as it reaches you.
2. Look at the water level in the vase. Most of our vase designs sit in water, not foam, so top the vase up with cool tap water.
3. Add the flower food packet we include with every order, mixed as the packet directs.
4. Set the vase somewhere cool and out of direct sun, away from radiators and heater vents.
5. Leave the design as it is for the first day. Dahlia heads are heavy and their stems snap and crease easily, so try not to pull them in and out.
6. Dahlias in green foam need the foam kept wet every day; don't pull the stems out.

For a hand-tied bouquet, fill a clean vase with cool water and the flower food before you unwrap. Then remove the wrap, cut about an inch off each stem with a sharp knife or clean, sharp scissors, strip any leaves that would sit under water, and put the stems in right away. Dull blades crush hollow stems, so use the sharpest tool you have.

Everyday care

• Check the water morning and evening in a warm, dry apartment, and top it up each time.
• Change the water every 2 days or so, or sooner if it turns cloudy, and add fresh flower food.
• Each time you change the water, trim about half an inch off the stems with a clean, sharp blade and get them back into water quickly.
• Keep them away from radiators, steam heat, sunny south windows and the direct blast of an air conditioner.
• Pull off any leaves that slip below the waterline. Dahlia stems foul the water faster than most, and clean water is what keeps them drinking.
• Remove any dahlia that has faded so it doesn't cloud the water for the rest of the arrangement.

For the full routine that works for every flower in the vase, see our guide to making cut flowers last.

Make them last longer

Enjoy them as they are. Dahlias are cut when they are already open, because they do not keep opening in the vase the way roses or lilies do. What you see on day one is the show. A small closed bud on the side of a stem will usually stay closed.

Cool nights help. Moving the vase to the coolest room overnight, away from heat, slows them down. They are not bothered much by ethylene from ripening fruit, but heat and dry air shorten their life quickly.

Keep the water clean. Growers describe dahlias as having "dirty" stems that are hard to hydrate. Fresh water, flower food and a fresh cut every couple of days do more than any trick.

Hot water for a wilting stem. This is an old florist method for hollow stems that have stopped drinking. Recut the stem, then stand the bottom inch or two in a mug or metal container of very hot water from a kettle that has just come off the boil (hot, not boiling), with the flower head well away from the steam. Skip a thin glass, which can crack. Leave it until the water cools, then return it to the arrangement's cool water. It doesn't always work, but it is worth a try on a dahlia that has gone limp. More rescue steps are in our guide to reviving drooping flowers.

Skip the home remedies. Sugar, soda, aspirin and pennies don't help dahlias. The packet we send is made for the job.

Common problems

Why are my dahlias drooping?

Almost always the stem has run out of water or has an air lock. Check the level first, then recut the stem and try the hot-water step above. A dahlia that is still limp the next morning is usually finished.

Why won't the buds open?

Dahlias open very little once they are cut, so a tight bud usually stays a bud. That is normal and doesn't mean anything is wrong with the flowers you have.

The petals on the back are turning brown. Is that normal?

Yes, that is how a dahlia ages. The outer petals behind the face soften and brown first. Once the front starts to drop petals, take that stem out and enjoy the rest of the arrangement.

The water turned cloudy after a day or two. What happened?

That is bacteria, and dahlia stems feed it. Empty the vase, rinse it, refill with cool water and flower food, recut the stems and put everything back. If an arrangement looks wrong within a day or two of arriving, call or email us within 3 days of delivery or pickup with your order number, the recipient's name and a photo (see our refund policy) and we'll take a look and make it right where we can.

Good to know

• Pets: the ASPCA lists dahlias as toxic to dogs, cats and horses, with mild stomach upset and mild skin irritation as the signs. Keep them out of reach, and if you think a pet has eaten some, call your vet or the ASPCA Animal Poison Control Center. More in our pet-safe flowers guide.
• Scent: dahlias have little or no fragrance, which makes them easy company on a dining table or a desk.
• In our designs: you may find dahlias with white hydrangea, callas and blush roses in Kakovatos, with white roses and stock in Erly Afternoon, in pink with raspberry hydrangea in Hy Love, and with orange roses and mini pumpkins in Fall in Love.
• Season: dahlias are a late-summer and fall flower, blooming from about midsummer until the first frost. Availability changes week to week, so call the shop to ask.
• Meaning: in the old language of flowers, dahlias are often linked with dignity and elegance.