If your garden looks tired at the end of the season, but your neighbors’ is full of color and texture, chances are they may be growing dahlias. Dahlias bloom from mid summer until frost, and come in small bedding sizes to large 3 foot plants with dinner plate size blooms. They are easy to grow with a few basic guidelines and tips, and will bloom when few other things in the garden will. Did I mention they are gorgeous? Great cutting flowers and pretty in the garden. What more could you want? Here’s how to grow dahlias, the easy way!
How to Grow Dahlias
- Dahlias are most often grown from tubers (like bulbs) planted in the spring. If you want the best varieties though, be taking notice of the plants that are blooming in early fall, and take note of the variety. One way to do this is to visit a nursery and check out plants in pots. I don’t recommend planting them from pots in the fall… they just aren’t a good value for the time they will bloom before frost. Start them in the spring for a longer bloom time and healthier plants.
- Choose tubers that are healthy and starting to sprout, or order online from a good quality company.
- When to plant dahlias- Plant in late spring after the soil is warm in full sun… don’t plant too early. A good rule of thumb is to plant dahlias when it’s safe to put tomato plants in the ground.
- Plant in rich, well drained soil, so that the crown is just below the soil. Don’t water until they start to sprout out of the soil They are prone to rot.
- For tall or dinner plate varieties, put several stakes around the plant. That is so that you can secure the heavy plant as it grows. Tomato or peony cages are good for this also, depending on the size you are growing.
- Fertilize every two weeks with a bloom fertilizer. Its important that you use a fertilizer low in nitrogen, (thats the first of the three numbers on a fertilizer) because too much nitrogen will grow big plants with no blooms.
- Keep well watered, but try not to water late in the evening, especially later in the fall. They can develop powdery mildew. if your area is prone to mildew (on roses, for instance) then you can use a commercial or natural anti fungal spray starting in July to prevent it.
- When your plant is 6-8 inches tall, pinch off the top growing point above the third set of leaves to encourage a bushier plant. Remember to clip off dying flowers at least once a week to promote more blooms.
- Dahlias can be hardy down to zone 7, but are usually treated as an annual.
- Learn how to store dahlia bulbs. If you want to lift your tubers and save them to replant next spring, do so before the first frost. Cut them back to 6 inches, and use a fork to gently pry them from the soil. Let them dry out for a few days, then store them in loose sawdust or vermiculite in an area that doesn’t freeze, such as an insulated garage.
- To cut dahlias, cut them in the early morning hours. BHG has this tip for making the blooms last… “After you’ve harvested dahlia flowers, make a fresh horizontal cut at the bottom of the stem and place the cut ends in about 2-3 inches of very hot (not quite boiling) water. Let the stems stay in the water for at least one hour. This hot-water treatment conditions the stems so the blooms will last four to six days.”
That’s it! Not that you know how to grow dahlias, here are some of our favorite varieties, both large and small! We recommend Swan Island Dahlias for ordering the best varieties online. Here are some of their choices…
Types of Dahlias We Love
Dreamcatcher – Grows to 4 feet with 6 inch blooms… This dahlia is a focal point for the garden!
Tahiti Sunrise – This spiky bloomer is a smaller plant, about 2 1/2 feet tall, with 5 inch blooms.
Bonne Esperance – A variety from the ’40’s, this single blooming pink beauty shows you that not all dahlias are of the double appearance… Low growing to 12 inches, this blooms early and long for a charming bedding plant!
Emory Paul – This is a large, dinner plate dahlia variety, growing to 4 1/2 feet tall, with blooms over 10 inches across! Support is a must for this variety that is often used for exhibition. Color is amazing!
Bridezilla – Dahlias can be just as stunning without all the flashy color… this white variety with a yellow “eye” would be gorgeous in any garden and would make a wedding bouquet worthy cut flower. Tall, at 5 feet plus, the blooms are 6 inches across. My fav!
We are planning on ordering a few of these for our garden now that we know how to grow dahlias! Pin your favorites for later! Jump on over to our posts on How to Grow Peonies and How to Grow Hydrangeas!
I live in Portland Oregon. Do I have to dig up my dahlias and store them over the winter?
Yes ma’am…
Can I save the bulbs that had powdery mildew and use them next year and not get it again? It’s been a bad year for it.
As long as there isn’t mildew on the bulbs themselves you should be fine. Let them dry out well before storing them. If there is mildew on the bulbs, however, its best to just toss them. They will likely rot in storage anyway.
I love Dahlias. I bought all the tubers Lowes put on clearance. I have over 100 growing In my back yard. I have learned how to propagate them from the stem. I am enjoying this method so much. I feel like I am creating something. Thanks Just felt like sharing.
Hi there, just came across your blog through Pinterest! I just bought my first couple tubulars and I’m super excited to plant them but a little nervous as I don’t really have a green thumb. I’m planning on mixing some compost with our ground soil but I’m a little worried about rot – I live in Oregon and we’re pretty prone to rain all through spring. Should I be worried? I was reading not to water until they first germinate. But if it’s already pretty wet should I not water until the soil is damp or semi dry? I just want to give them the best chance possible!:)
If its already pretty wet, then don’t water them until they are semi dry, but don’t let them dry out all the way. I know that when you have a rainy spring, its a guessing game sometimes! Dig a bigger hole then usual and mix as much compost as you can to improve the drainage, and you should be ok! Hope that helps!
Need recommendations on how to plant Dahlia lavander ruffles trying to make a garden for the wife
Hi Michael! How sweet of you! We love ‘Swan Island Dahlias’ and they have a great resource on growing them at http://www.dahlias.com/howtogrowdahlias.aspx
Are they deer and rabbit food? They are beautiful flowers.
While there is some controversy about the level of deer resistant dahlias are (some say they are, some say they aren’t) I’m pretty sure rabbits would have no problem making them a snack.
Has anyone planted Dahlia in containers ??
There are lots of dahlias that are great for containers, look for the smaller (under 16 inches) varieties!
Hi! I thought I read somewhere that you can bring dahlias inside in the fall /winter and the will continue to grow?
We’re not aware of bringing them in to grow through the winter, like most bulbs, they need the winter to rest so they can bloom again the following year…
Hi, I came across your blog through pintrest, I have had huge success with growing dahlias from seed, I ordered a pack from aliexpress (300) and started them in a seed tray (randomly thrown in). They didn’t germinate immediately so I put some more into other seed containers. Then they all germinated and I had 89 seedlings.
I have really enjoyed seeing what would come up so I have done the same again this season. (We have just had the first day of spring).
Can’t wait to see what I get this year… I am actually after a blue one so I have a lot of experimenting still to do!
I also have tubers that I leave in over winter and they usually grow again and we get quite heavy frosts. Although I dug some up but by reading your article I think I was a bit late with that.. We will see. Thanks again.
Do I have to dig dahlia bulbs in the fall
If you live in an area where the ground freezes, yes!
Hi there,
Thanks for the great Information, however I do have a question about earwigs, I’ve planted dahlias before and seem to have had an infestation of the little pesks. Makes me not want to plant them anymore, Any tips would be greatly appreciated.
Thank you
Some plants do attract a certain type of pest… found this for you! http://forums.gardenweb.com/discussions/1838802/earwigs-on-new-dahlia-shoots?n=5
i have planted several colors of dahlias. When I bought them at the store, the blooms were a deep red and another a deep purple. I brought them home and planted them and the colors of the new blooms have started to change. The red is now light almost rust colored and this morning a new bloom looked purple. Do dahlias change color depending on the soil? Like Hydrangeas?
Not that I’m aware, but they can change a big in their saturation if they get too much after noon sun… Has anyone else had this experience?
I live in zone 5b. I was wondering if I could leave the dahlia on the ground over winter and cover it with mulch and will they come back in spring?
Probably not…they really are not hardy… Anyone tried this?
I live down south i dug up some dahlias this year because they were in the wrong place or to large for the pots i put them in. Bad mistake on my part as they went rotten over winter as i proberly did not dry or store them properly. the ones i left in ground covered in mulch are all ok so this year they will all stay in.
I love dahlias but something attacks them every year I think it might be earwigs! So fed up they get shredded even if I keep them in pots
Any ideas?
A preventative broad insect spray early in the season, whether organic, or something like Sevin should do the trick!
I have grown the dahlias and have trouble with earwigs. I have tried several sprays Seven and nothing seems to work. Do you know if I should spray around the plant or right on it? Does cedar mulch help?
You want to spray the plant itself, but not during the hottest part of the day… Mulch actually can make it worse, since they like to hide there during the day, so pull back any mulch if you have it. You an try traps that are used at night, just Google it for ideas. An empty tuna fish can with the oil drained, then returned to the can after removing the tuna is supposedly irresistible to them, then they get stuck in the oil in the can. Set this out at night. Good luck, and remember, with pests, consistency is key!
I love Dahlias. They are my favourite flower. And ‘cafe au lait’ is my absolute favourite. It’s the most stunning flower ever!
I always start my dahlias indoors. I pot them up in April and keep them in my unheated greenhouse until I’m ready to plant out in May. By then they will all have healthy shoots and are a bit better at fending off slug attacks!
I have terrible, heavy clay soil and have not had much luck with dahlias. I planed them the first year and they were beautiful all summer, but the winter rains caused them to rot in the ground. Do you have any advice on how I could grow dahlias in my yard? Also, if I amend my soil what do you suggest I amend with? Thanks for any help you can give me!
You can amend with compost, but you should consider containers! A lot of the smaller ones will do containers well!
The problem I’ve had is Earwigs in my blooms. I have to hose them off before I bring them in the house, then they’re all wet so I can’t put them on the dining room table. Solution?
I lifted my dahlia tubers last fall forthe first time. Can you get the tubers started early inside with a grow table? Also, is there anyway to tell if the tubers are viable before planting?
Thanks,
Has anyone started their tubers early indoors? Healthy tubers should feel heavy and not shriveled… usually you will see signs of new growth as well…
Oh boy do I! We live in Whitehorse, Yukon and if you have a passion for dahlias you have no choice but to start them early in doors. March rolls around and our garage turns to a thriving dahlia nursery. Tables and grow lights-a-plenty! Last year we did 52 varieties and treasured every single one that bloomed. Lots and lots of fresh cut flowers for all our friends, neighbors, coworkers, total strangers etc. for weeks!
We grow them in pots. When they’re ready to stay outdoors (2nd week in June), I just wiggle the pots down into the dirt and they look like they r planted. Nice thing is that we can move them around if we want. After the frost gets them (1st or 2nd week in Sept) we let the greens die back for a couple of weeks, trim the dead stuff down to about 1″ and then back into the garage they go for their winter nap. The garage is kept between 5 and 11 degrees. They have to b divided every 2nd year. It’s not for the faint of heart but they r just so darn showy and wonderful. Lol.
Hi, I’ve been growing Dahlias for many years and love the extended color they give. They are also very good at conditioning soil. I plant a circle about 2.5 ‘ apart around newly planted fruit trees. They are about 4’ out from the tree. The Dahlia roots help break up the soil and attract beneficial organisms. The first year I’ll dig them up and plant flower bulbs in the holes. the Second year again in the alternative spaces. . The third year the trees are usually 2 big to want to disturb the tree roots. SO I plant the extra Dahlias that I have duplicates for and don’t expect to dig them.I just leave them in the soil to compost.
I absolutely fell in love with Dahlias this year! I bought a variety pack of dinner plate tubers from a local home improvement store and put them in containers right out front surrounded by pansies. They grew well and have given me some amazing blooms! Two of the plants have blooms that have each been a variation along the same color scheme.
I also bought a Dahlietta that didn’t seem to be doing very well until I planted it with nothing else around it and now it is healthy and bushy and blooming like mad!
Thank you for the article! I actually killed three Dahlia tubers last year by over watering them because I had no idea that they were prone to rot early on.
The tubers need to be planted sideways/lengthwise, not vertical like most bulbs. I live in zone 8 and cover my dahlia bed with black plastic and mulch and divide in the spring.
I have hanging baskets that I took in overwinter. I wasn’t sure what was in them other than a tag I had left in one of the baskets that was labeled Dalia and had pulled up several healthy bulbs. I am very excited to have them grow. I did separate the bulbs but did not re pot them sideways I put root side down. Also I think we are in zone 9, Buffalo, Ny Can I put them in my garden and will I have to dig them up in the fall ? Thanks
You will have to dig them up if you want them to come back next year.
Hi Kathy,
We would like to send a thank you to you for such an amazing article. Can you please email me with your contact info? info@dahlias.com – Thank you!!! :)
Inverlochy Castle in Scotland has a walled garden with the most beautiful and diverse collection of dahlias.
I love seeing my pictures on your post! Big smiles!!! Glad you like them as much as we do!! I am proud to be a part of our family owned and operated dahlia business – celebrating its 88th year! Please view these and many more on our website http://www.dahlias.com
I planted “miniature” dahlias & love them! I thin the bulbs every spring into other flower beds & have had great luck with them. They grow better for me than the large dinner plate dahlias, which I also love but don’t have any luck with :(. Your post has inspired me to try them again!
Thanks for sharing your experience Gracie, and I’m glade you’re going to give the larger dahlias another try… I am going to be planting “Bridesmaid” that we featured in the Spring myself!
Hello Kathy. I am new to this site and see that you are an expert with dalhias. I am new to this flowering beauty and all the varieties. i recd a package of dahlia seeds which I planted in potting soil put in 18 egg shell halves then put the halves back into the cardboard egg carton with lid removed and placed it underneath the carton with the seed plantings. five days later the seeds had already germinated. it is now 12 days and I need to replant them in a larger container. I’m thinking I’ll use an empty window box as that should give each plant plenty room to grow a stronger root system. How am I doing so far? My questions: you speak of tubers and bulbs, however, I am working with seeds. Am I wasting my time? What is the between them? Thanking you in advance, I am Grama Debbie Happy Planting
I have never grown them form seeds… the tubers are a much easier way to grow anything, but that having been said, I think if they are doing well, get them in very bright light and give it a try!
Hi Grama Debbie! I have grown dahlias from seeds several times with great success! I was surprised to see that by fall there was hardly any difference between the plants grown from tubers and the plants grown from seed. Both had lovely flowers and big tubers to save for next year. I planted a dahlia seed mix, and it was fun to see the variety. It’s an inexpensive way to get a variety of beautiful dahlias! Hope yours do very well for you. :-)