The Challenges of Growing Dahlias
Each year I always look forward to the summer when dahlias are blooming. I start out in January and February waking up some dahlia tubers so I can take some cuttings. In late March, I am starting some dahlia seeds that I saved from my dahlia garden the previous year. The tubers are starting to warm up in March and April and begin to show sprouts. It is an exciting time. I live in northern North Carolina just above Winston-Salem and Greensboro. My location is in plant hardiness zone 7B; however, I am on the edge of plant hardiness zone 8A.
I try to plant my dahlia tubers in late April and May. I like to have the plants growing before it becomes so humid in June as that type of weather slows down the dahlias. I have planted later in late May and June and that works but sometimes when we have a tropical storm in early August, I can lose some dahlias. It depends on the weather that year but if I plant in early June and it is very hot and humid, the plants are so slow growing. Usually by July, they should have some nice growth but with the heat and humidity, they can still be slow growing. If we have a tropical storm in early August, I can lose some dahlias from the excessive rainfall and that is so frustrating. That is why I try to plant the dahlia tubers in late April. It is going to be different for each of us as it depends on our climate and soil conditions. With dahlias you can do a succession planting so you can have blooms throughout the growing season.
This year, I was able to start planting around April 18th. I had around 1300 dahlias to plant, so it took me several weeks. I was also planting my first-year seedlings. I planted around 1460 seedlings that I started from seed in March. I finished by May 20th.
I wrote a blog at the end of July about growing dahlias in the heat and high humidity. I talked about the hot, humid, wet summer we had. Now it is December and what a year. The weather really does have such an effect on your flower and tuber production. I started digging up any first-year seedlings that I was keeping at the end of October. I was happy with myself this year as I tried to only save the very best dahlia seedlings. I only saved 7% of my first-year seedlings. I really need to get that down to 5% as it takes up a lot of space in the dahlia garden. Once I had the first-year seedlings dug up, I started to focus on my other dahlias from seed. You do not have to wait for a frost to dig up your dahlias. Dahlias need 120 days to produce tubers. My dahlias had been in the ground for 5 months. I do like to wait until we have a hard frost as it gives the tubers more time to mature and harden. I normally start digging dahlias around November 10th and hope I can finish in four weeks. I have around 1300 dahlias to dig, and I do this mostly by myself. As I am getting older, it is something that I do like to have completed before cold weather arrives. I am in the over 60-year-old group! Lol. December used to have temperatures in the 50’s, which is our average temperature for that month; however, the last two years, December has been below average. As I write this blog, December is 10 degrees or more below average. We also have so many nights in the 20’s which is cold for our area. I am so glad I finished digging, dividing, and packing dahlias by December 5th. I did lose some dahlias due to our wet season. I also reduced some of the dahlias from seed that I am moving forward to allow me more room for the dahlias I am selling. This helped me to finish early also.
When I started digging, I saw some vole damage in my first 12 rows. The voles or field mice had not bothered that section. They had bothered my last 8 rows so in 2024 I put down Permatill and that really helped a lot that year. I had added some Permatill to the first 12 rows but not a lot. I like to use it on top as it keeps chewing insects away like snails and slugs. It takes time to add that Permatill to your soil and slows you up with planting. I am trying to plant as fast as possible. Weather can be an issue. After seeing the vole or field mice damage to the tubers, I will need to add more Permatill to all my rows of dahlias in 2026.
Permatill is a brand name for a type of expanded slate soil amendment. Expanded slate is a lightweight and porous material made from natural slate that undergoes a process of expansion at high temperatures. Permatill is used in gardening and landscaping to improve soil structure, aeration, and drainage. Stalite Environmental in Salisbury, NC produces this product. I found it at a local gardening center. Permatill helps discourage voles because voles do not like to dig through materials that are coarse in texture. I mixed it into my soil as I plant dahlias.
You can use Permatill has a mulch at the soil surface as it can help reduce soil borne diseases on the stems and foliage. Also, slugs do not like to crawl on Permatill. Voles can be persistent and can dig into the roots from the surface, so this is extra protection. Also, the Permatill acts as a weed suppressant.
I do see some lenticels on tubers. During a wet growing season, you may see these odd-looking bumps on the tubers. These are lenticels. This happened because the tubers had been exposed to a lot of water in the soil. These lenticels do not affect the tubers and are harmless. So, when you are dividing tubers, remember that lenticels are just a reaction from the tuber being exposed to wet soil. These lenticels do not look so bad once you wash the dahlia tubers, and they have dried. The tuber is fine and will sprout and grow into a healthy dahlia.
For some reason, Paula's Paul Wix made tubers early so they are mature and many of the tubers had splits for some reason. I don’t know if he is a little sensitive to fertilizer or if it is a reaction to the wet season. The tubers will still sprout and grow into a healthy dahlia; however, I really do not want splits in the tubers.
Since dahlias are producing the tubers underground, you do not know what is going on underneath the soil. When you dig the dahlia tubers and see the issues you are disappointed. You work so hard during the hot humid summer to keep the dahlias alive and happy as they really do not like humid weather with nighttime lows in the 70’s. The dahlias have no time to rest at night. The dahlias slow down growing and blooming. If they do bloom in July, they are not the best blooms as the heat and humidity has caused them to open too quickly. Usually in late August when the nighttime lows are becoming cooler, the dahlias are their best and bloom so beautifully until we have our first frost. When you dig the dahlias to store the tubers over the winter, you want to see beautiful tubers. For me, some of the dahlias did well with the wet season and other dahlia seedlings did not like the wet season. Since I was having my first dahlia tuber sale with my own dahlias, I need good tuber production. Dahlias are a lot like sweet potatoes. When I read about sweet potato production, I read about what causes sweet potatoes to crack. Apparently, this is usually caused by excess water. You do not want to water sweet potatoes at the end of the season as this is the primary cause of split or cracks in the sweet potatoes. You should stop any irrigation a month before harvest. I did not use my drip irrigation much this season because we had a very wet summer. You cannot stop Mother Nature from giving us rain in October and November. Tuber production is supposed to really begin when the days have less than 12 hours of daylight which begins around September 26th in my location. So, October is an important month for tubers production for me. Some dahlias cultivars start making tubers early so when you dig up the tubers, they are very mature looking.
Our land does have some high and low spots. The rows do slope a little. We added some pressure treated lumber along the first row of the field to direct the water away from the dahlia rows. My husband made some brackets that are hammered into the ground to hold the board in place and tight to the ground. We can have some really heavy thunderstorms with a lot of rain in a short amount of time. This did help.
You can have sweet potato splits from fertilizer also. I read where you do not want a lot of nitrogen fertilizer on your sweet potatoes as this can produce lush vine growth but split potatoes. In fact, some articles that I read said sweet potatoes do not need nitrogen and to focus on potassium. Some dahlia growers do use potassium in August for tuber production. I have talked about it in prior years. I usually use a low fertilizer from May to the beginning of August. If I have time, I try to add some potassium to my soil in August. I was reading that some growers use a natural Sul-Po-Mag which is a natural occurring crystalline material known as langbeinite. It is a source of potassium, sulfur and magnesium. Potassium does encourage root growth and helps the plant resist diseases. Again, soil tests are important. Since my soil tests show that I am high in phosphorus and potassium, I am careful about adding too much to my soil. When I dug up my tubers, my soil is so nice, loose, and well drained.
We did have a one of the hottest July on record. Raleigh, North Carolina had the hottest June and July on record. Raleigh is only 2 hours from my location. We broke so many records for consecutive nighttime lows over 70 degrees. Any stress on the developing tubers will affect tuber production. Stress is temperature fluctuations, high temperatures, and a wet season. It is hard to predict the weather. You just deal with each growing season and try to learn something to help you the next season. We are always looking forward to the next year and hoping the growing season will be better.
It takes a lot of work, time, and patience to do all this. I do it because I enjoy growing dahlias. I am a very small grower. I will try my best to increase the number of dahlias next year for sale. I am happy I will be releasing Paula’s Raven this year. It began its life back in 2022. It is a ball form as the petals roll inward for more than half the length. The petals form little hearts. The bloom size is around 3.5 inches; however, if you do not disbud the bloom size is smaller.
I am releasing Paula’s Paul Wix, Doris Jane, Mollie Sue, Ellie, Miss Confident, and Raven. I plan to do an American Dahlia Society seedling bench evaluation with Paula’s Divine in 2026. I also submitted my application to a couple ADS trial gardens and one trial garden accepted me. The other trial garden was full already. I look forward to sending Paula’s Divine tubers to the ADS trial garden in April of 2026.
I also plan on showing Paula’s Stella Ann at ADS shows next year. Paula’s Stella Ann has the stellar form where the petals are long and narrow along the petal length with pointed tips. The stellar form does have space between the petals in each row of petals but still maintains a uniform, regular arrangement.
I am continuing to evaluate these seedlings are they go into their third year in 2026. Paula’s Candy has so much petal count. She really stands out in the garden. Paula’s Candy may be too sweet for some people, but I think a lot of people would enjoy this dahlia in their garden. The yellow and pink combination is eye-catching!
Another seedling I am evaluating is Paula’s Quill. Quill wants to have semi cactus form as the petals roll back along the petal length for approximately half the length and fully overlap at the tips for almost one fourth their length. The bloom size of this seedling is 6 to 7 inches across. Dahlias are so much fun to grow as they come in so many different forms. I think the cactus form is interesting.
I am increasing the number of plants of Paula’s Dusty Rose in 2026 so I can release this dahlia. The color is such a warm, earthy tone that makes you think of fall. This dahlia performed well during our hot humid summer. I have been growing this dahlia since 2022, and it was saying “please notice me!”. The dahlia has dark stems, great growth habits and foliage, and it was very floriferous. I found myself going over to the dahlia several times during the summer and I was impressed with the overall performance. It really does take three years or so to really see how a dahlia from seed will perform each summer and fall as mother nature is in control with each year being a little different. Paula’s Dusty Rose produced long, sturdy stems for cutting.
My first dahlia tuber sale of my dahlia tubers is going to be very limited. I have a Garden Bee Hive club that is very limited and consists of people who have been following me for several years. The Garden Bee Hive Club has first access to my tuber sale. After that, I announce it on my Instagram stories and to my website subscribers, but it will all depend on the amount I have available. I wish I had more tubers to share. It is never going to be perfect. I hope to have more tubers available at my next tuber sale in December 2026. Thank you for following along with me on my journey with growing dahlias from seed. I am happy to share something from my backyard to your backyard. I hope you enjoy the dahlias as much as I do. Thank you for your support! I am really excited to finally sell some of my own dahlias from seed!