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?
Dahlia Bed Prep- Raised Beds
This is a post I probably should have written years ago based on the number of questions I get about how to fill a raised bed. I’m speaking to this topic from the viewpoint of dahlias but it can be used for general gardening purposes as well.
Raised beds are excellent places to grow, especially if you live in the land of clay soils like I do. Years ago when we moved on to our farm, I saw a sloping hillside and instantly knew that raised beds were my answer.
So let’s talk about the benefits of raised beds:
1. Erosion control- this was huge for our farm because everything is on a hill. The only flat land is our front yard. You don’t necessarily have to have permanent sided raised beds for erosion control- this was the route we choose but even mounded rows will work.
2. Drainage- We know dahlias need good drainage. They don’t like sitting in water. You don’t have to go super high on your raised beds either, especially if you have a bit of a slope. With a slope, 6 inches is about the minimum for how much you want to be mounding your dirt or the depth of your raised bed. On flat ground, go 8-10” if you can. Deeper is always nice but not totally necessary. However, sometimes deeper means a higher bed so you are supporting your back more- totally on board with that the older I get!
3. Timing- Raised beds warm up faster allowing you to plant a bit earlier and also allowing you to plant after heavy rains. We got several days/inches of rain recently. The morning after the storms, I checked the raised beds in the field and the moisture level was perfect for planting tubers! I’ve never had to wait after heavy rains to plant because of my raised beds.
4. Labor saving in the long run- Raised beds are more prep work financially and timewise in the beginning but save so much time over the years because you don’t have to re-till and reshape every season. They are also easier to keep up with weeding because you are usually filling with fresh weed free soil. So if you keep on top of it from the beginning, you won’t spend hours weeding.
Have I convinced you yet? Nothing wrong with in ground growing but I gotta’ admit I love a good raised bed!
Deeper Raised Bed (that needs a little repair work!)
So what are we going to put in that raised bed?
I’ve started raised beds 2 ways and they both work great- one is just a little more work.
Method 1: Mow your grass very short— scalp it. Then cover the area with cardboard and construct your raised bed on top of it. The cardboard will kill the grass overtime and break down. This is the method I use in my vegetable garden.
Method 2: Till the area and get all the grass/weeds out and then construct your raised bed on top. This is the method we used in our flower field. (It would have taken a lot of cardboard.)
After you get your grass killed or area tilled, it’s time to fill it up. I start with a layer of branches- not big ones, nothing bigger than 2” in diameter. Trust me on this one— 2 years ago my husband designed an amazing raised bed for our vegetable garden, he built it and then began filling it with branches— and logs! He knew that branches were what I used in the bottom but I didn’t realize he had put logs in there until the dirt was already on top!! So needless to say, it’s still breaking down. I’ve been growing plants from the cucurbit family in that bed because they don’t mind a compost like environment. It will be beautiful soil - one day!
Once your branches are down, I add leaves if the time of year is right. Leaves are an amazing soil additive. If you can get them shredded- even better. If they are shredded, you can add a lot. If they are freshly raked, don’t put so many that they mat up when wet.
It’s finally time for the soil! You want a good quality compost. Now what is that and how do you find it? #1- Ask gardeners in your area. Compost is going to be different regionally. #2- if you have time, buy a small amount and get a soil test done before committing to a large amount. I always recommend getting a soil test done on your base soil regardless but if you can get it done before you buy- even better. Some companies may even be able to provide you with a recent test done on their soil.
You don’t have to use 100% compost. You can mix it with some top soil if you can find good quality top soil. All compost gets very expensive. This is where a lot of the financial investment comes into play with raised beds.
Compost can come delivered in bulk or you can buy it in bags. Bags are usually a bit more money wise but they are also faster because you don’t have to shovel and wheelbarrow the soil across your yard. When we set up our flower field originally, we used bags because of the geographical topography of our farm. We didn’t have a tractor with a bucket at the time, so I figured that moving bags was less labor than having to shovel and push a wheelbarrow several hundred feet to the field (and down a very steep hill). I just bought a pallet worth of bagged compost at a time. I tell you this because some people have a misconception that buying bagged compost is crazy but if I can do a 1/2 acre field this way- it’ll work for your backyard garden!
My husband’s raised bed design that is far superior to mine! I love the rocks on the bottom.
If you have bought in good quality soil, then hopefully your soil is well balanced nutrient wise. If so and you are planting dahlias, then I would add a granular fertilizer - something like a 10-10-10 or something with a touch higher nitrogen than phosphorus and potassium to start.
(For more dahlia fertilization recommendations, go here).
That’s my method for filling up a raised bed— What’s yours? I always love to hear new tips and tricks!
