Wilty Dahlias
Are your dahlias sad? Do they droop and sag? You’re not alone! Unfortunately dahlias don’t always look happy and healthy- especially when growing in a hot climate.
So let’s talk about some of the possible causes:
We’ll start off with the obvious: Water— either too much or lack thereof
1. So if a dahlia wilts, the most likely thought is- It needs water right? Well that’s the first thing I check. Stick your finger down 1.5 inches into the soil and test the moisture level. If it’s dry, then it’s a good chance it does need water. But it’s also worth checking a few other things!
2. I always try to feel down to the tuber- you want to make sure it’s not rotting. If it’s rotting, then this is more likely the cause of the wilting. There’s not a ton you can do if it’s rotting. If it’s early enough in the season, I try to grab a cutting off of it. Or sometimes I will cut the plant back a little bit so that the tuber isn’t supporting so much green growth. But in reality these are last ditch efforts- you are probably going to lose it.
3. Now if the tuber is firm and the soil is moist - well that leads us to the next possible cause:
Verticillium Wilt- This is a soil borne fungal disease. It prevents water from moving through the vascular system - therefore showing up as wilting, yellowing foliage and dieback. There’s not a lot you can do unless you catch it really early. Sometimes you can chop the plant back hard and it will recover but you have to catch at the first sign of wilt. The problem is that it usually affects the plant in the lower portion of the stem and blocks water flow to the upper parts- which is why it’s so hard to deal with. Don’t compost any plant parts that you remove.
Prevention can help but it’s not a sure way to keep it away. Using a fungicide spray regimen before you see any signs can help prevent it or slow the onset. Soil solarization where you find it can be helpful too. But unfortunately, it’s usually a death sentence if you catch it too late.
Browning Leaves and Black Tips on new growth are also commonly seen in wilty dahlias. The browning - if it’s seen higher up on the plant is usually a sign of sun scorch. Lower brown leaves- like around the base of the plant may be signs of fungal issues. Black tips on new growth near the top of the plant are signs of a boron deficiency (Cafes love to get this!).
Next time you see a wilty dahlia, you know where to start to diagnose the problem! Want to be the first to know when we release a new blog post—
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The Radish Experiment
We grow a lot of our dahlias at an offsite plot and the owner of that plot has chickens. During the winter we often use daikon radish as part of our cover crop. Turns out that the chickens love the radish greens.
Well obviously they disappear once we terminate our cover crop so I decided to try an experiment so the chickens can have more radishes (and hopefully keep some weeds down) Anything for the chickies!
We have 2 rows of dahlias in this plot that are planted 2 across in a 4’ wide bed instead of the 4 across that we usually do so those rows tend to get very weedy on the edges.
These are the hurricane survivors by the way. It took them awhile to get going but they look great now!
So I went to my local feed and seed and bought a pound of radish seed and sprinkled a row down the edge of the bed. I seeded pretty generously so that there would be enough to help cover the soil and prevent weeds. But also so we could have enough to pull to feed the chickens.
We got a great rain the evening after I sowed these so hopefully in a few days, we will see little radish sprouts! I’ll keep you posted.
Update (7/23/25)- Radishes germinated well but I definitely need to work on seeding evenly. In the left picture you can see a 10’ stretch of row and how it’s a bit sparse in some areas. The right picture shows a close up of a well seeded area- This is what I’m going for. I reseeded after I took these pictures and we had good rain yesterday so hopefully the second time works!
So What If the Rain Won’t Go Away?
This is another one of those “if I had a $1 for every time” posts—- All I’m hearing about right now is “Are my tubers going to rot?” It’s been a very wet year so far in the Southeast. I’m writing this only a few hours after our power came back on - we just had a huge storm that dumped a ton of water. And it’s been raining almost every day!
So let’s talk about DRAINAGE!
First off- the reality. There’s not a ton you can do to fix bad drainage for the immediate future. But there are a lot of plans you can put into place for the long-term future. So let’s make some future plans!
What exactly is good drainage in soil? Good drainage is when the water can pass through your soil at a moderate rate. Clear as mud right? Realistically you want the water to not pool on the surface but also you don’t want it to dry out too quickly. But we all know that sometimes the water comes down too fast for the soil to be able to handle it efficiently. After a heavy storm, it’s going to pool on top. My personal measurement is- “Does it drain off in less than 24 hours?” If so, all good. I have heavy clay soil so if it can drain the water from a pooling point in 24 hours or less- that’s not half bad.
But what if the water is standing for days? How do you fix poor drainage in your soil?
1. Organic Matter- Soils that are high in organic matter hold water but also let it pass through. They are kinda like sponges- plenty of holes to let unnecessary amounts of water through but will hold what it needs. You can get more organic matter in your soil in several ways. Adding compost is one of the easiest. Compost is just all the leftover waste from your garden and it turns into black gold. Compost not only adds nutrients but also add organic matter to your soil which will help handle how water moves in your soil.
Shredded leaves are a another excellent addition. You do want to make sure they are shredded- whole leaves will just create an impenetrable mat that breaks down slowly. We bought a leaf shredder for the farm 2 years ago and have been adding shredded leaves to our beds each fall. It’s making a massive difference and it doesn’t take that much either. We put about the equivalent of 2 unshredded wheelbarrow loads in a 4x16 area. So it’s a pretty thin layer but it makes a world of difference.
We began mulching our dahlias with straw 3 years ago and as it breaks down it’s turning into great organic matter for our soil. I love a product like this that does double duty!
2. Gypsum- This stuff is magic! I’m not totally sure how it works but 2 years ago we did an application of gypsum on almost our entire farm. It takes a bit to really see the benefits but 2 years on, I can tell. There’s a difference in the few areas that didn’t get the application. And the awesome thing about it is that you can’t over apply it. If your soil doesn’t need it, it just holds it until it does. Gypsum adjusts the tilth of your soil and for clay soils, this is a game changer.
3. Lay of the land- Don’t discount growing on a slight slope. I thought it would be hard when we began our farm but on wet years like this, I’m so thankful for a slope to grow on. And you don’t need much. If you are prepping a new area to grow in, give it just a slight slope, it may not even be noticeable to most people but it will help move that water off.
Raised beds will help with this if you are on a flat land situation (and even if you aren’t). You can do permanent style beds or just rake the dirt up a few inches.
4. Drains and Grading- Depending on how bad your drainage situation is, you may need to have portions of your land regraded or add drains. We had to have some of ours regraded back in 2018- it made a huge difference. And then in 2020, we added a huge drainage ditch at the top of the hill (top of the flower field) to catch water coming down from above that. Physically changing the water flow made a huge difference!
So if you are having drainage issues this year, it’s time to make a plan for the off season. I promise you it will pay off in the long run. I feel like everything we have done to improve our drainage on this farm has been for this season! So bring it on rain! (but leave the hurricanes in the Atlantic please!)
2025 2nd/3rd Year Trial Varieties
If you’ve ever asked me how many varieties I grow, then you’ve heard me laugh. Way too many is the usual answer. But I believe that figuring out which varieties are heat tolerant is a worthwhile endeavor. So I take the dahlia trials very seriously and therefore why I grow so many varieties. Here’s a little sneak peak into some of my 2nd and 3rd year trials.
So what does 2nd and 3rd year trials mean? I grow a variety for a minimum of 3 years before I will say it’s heat tolerant. Three years usually lets me see it go through all kinds of weather patterns. Sometimes I can tell in year one if a dahlia is not going to cut it, sometimes it will do great years 1 and 2 and flop on year 3. But anyways, let’s get to the pretty pictures.
Normandy Bright Day- she’s a second year trialer- a bit more peach than she appears in the photo. I’ve got high hopes. I did a bit of propagation to increase our numbers so I could see what she would be like growing en masse.
KA Cinder Rose- Loved this one last year, early bloomer which is always a plus. Great coloring! I’m learning to grow out KA varieties for longer than the 3 years. The California climate where they originate is quite the opposite of here so I think a longer testing period is needed to truly see their capabilities in our climate. I’ve got high hopes for this one!
Diana’s Memory- I had this is production several years ago and always loved it but it’s a hard one to store through the winter— skinny tubers. So if it stays it’ll be available as rooted cuttings and we’ll probably grow it on the farm in a perennial fashion.
Camano Zoe- in her high heat coloring. She gets whiter with the pink more concentrated in the center as the temps cool. 2nd year on this and I’m seeing lots of promise.
Hilltop Lost Treasure (left) and Brookside Cheri (right)- I’ve been growing Hilltop Lost Treasure for years because she’s a personal favorite. I’ve been trialing Brookside Cheri for 3 years and had decided to cut it last fall. But then I ended up keeping a few tubers. So we’ll see what happens- they aren’t planted yet. But this is a good example of the hard decisions you have to make. They are both great but they are very similar and there’s only room to keep one. Who would you choose?
