3,226 Garden Web Discussions | Dahlias
Thanks for the feedback.
But please understand I still don't know what, precisely, you mean by water them well. As in how much -- 1 cup? 2 gallons? or what?
As an example of how much detail a long-distance diagnosis requires, consider this when I tried to troubleshoot a veggie problem over the phone. The description sounded like a water shortage but the gardener said that "It can't be; I water daily." Then, after further questions from me, I learned it was with a drip system. Then, after still more questions, I found out the drip system was on for just 5 minutes a day. (Yikes!)
The diagnosis: insufficient water in spite of daily watering.
Okay, back to your dahlias. Here are some things to consider.
Are these new or established plants?
If new, the original rootball is most likely drying out,this because it is "missed" when you water. The water would have to be applied directly on top of the rootball, possibly drizzled rather than poured from a can or hose.
If established, perhaps you aren't adding enough water.
On the other hand, the roots might be drowning. Have you checked just how moist the soil is? (To tell the truth, I doubt they're drowning because the leaves don't show the correct symptoms.)
How hot and/or dry has it been recently? Also currently is?
Do you have burrowing critters? Moles can tunnel under plants, thereby redirecting water away from roots. And gophers just plain eat roots/plants
I suggest a water shortage from whatever cause because of the dried leaf edges and tips.
You will need to be our on-site detective.
Check the soil moisture content.
Perhaps even sacrifice a plant by digging it up so that you can see what's going on in the rootball.
Let us know what you find.
Sorry to hear about your bad experience. All my dahlias are from tubers.
It is probably too late to order for this year, but keep this list in mind for next year.
Here is a link that might be useful: The Big List
It sounds like you have spider mites. Take a piece of white paper and put it under the leaves where you see the spider webs and shake the plant. The mites are usually on the underside of the leaves. If you have red or black things hit the paper then you can see them and they will leave a residue when you crush them with your finger. Also, the leaves are browning from the bottom of the plant up indicate spider mites.
Getting rid of them is the hard part. The best product is Avid which has a systemic action but is VERY expensive to purchase. Next find a product that says will kill spider mites, and maybe some others can make recommendations to you. Whatever you use you need to use it three times about three days apart so you kill them in all stages of development. You must spray on the under sides of the leaves. Then spray for them weekly as a preventive measure.
If not killed they will kill every plant they get on in your garden.
Take a look at the DS of Georgia newsletter for June 2007, Page 4, and July 2006, page 2 for a discussion of spider mites and other bugs.
Here is a link that might be useful: Dahlia Society of Georgia
I have been growing dahlias for several years, usually from bulbs. Last year I was anxious for blooms so I bought two blooming plants. The dahlias grown from bulbs were wonderful, but the established plants I bought were terrible.
One year I started the bulbs inside, but they didn't do any better than the bulbs started outside.
I LOVE DAHLIAS
I find that they don't get quite as tall after pinching, but they are fuller and give more flowers. However, mine grew to close to 4 feet last year after pinching. If one wanted to "show" your dahlias in a competition, then one would be better not to pinch, getting larger flowers and straight stems. If one wants more flowers, pinch the leader and get more flowers, albeit a little smaller flowers.
What I have heard about dahlias and deer is that if a mother
deer doesn't know that they are edible she will not teach her fawn to eat them...but if she does know and eats them then she will teach all her children that that they are good food! It seems to me that she tells all her girlfriends too so they then tell their younguns that they can eat them!
When I lived at the central part of the island they did not bother my dahlias at all. I moved to the southern end and The only ones I can leave outside the fence are some around the driveway tucked into the lilacs. They did get a few nibbles last year but did not get eaten down to the roots.
THen my ducks discoverd that dahlias were good and ate all the fancy ones in my mixed perennial and rose garden by the front door..inside the deer fence.
This tells me that deer and ducks do communicate...and will gang up on you!
So far this year the deer have not discovered the dahlias growing in a parking strip bed that has lavender and cannas and alliums. Origonally it was to hold all my most special dahias but that idea did not last long!
Never trust any animal around your dahlias. If it does not eat them it will take a nap on them!
I always pinch off the lower leaves, as it allows for better air circulation, and hence there is less probability for mold to start. Do both,- add soil and pinch off the bottom leaves to about 6 inches above the soil when it is tall enough. The plants will love it.
Thanks jroot, that is what I'm going to do. I have a heavier container mix in my potted dahlias and I was reluctant to bury those leaves for fear of rot. The ones planted out in the garden still have a little way to go before I can pinch so maybe I'll experiment with some pinched and some buried.
How cold does it get where you are? How deep does the ground freeze? If the tubers freeze at all they will rot. I leave mine in the ground here but I cover them with about 6"of straw. We had an abnormal cold spell with temperatures in the low 20's, maybe down to 18 degrees last winter. I lost some of the ones I had moved in the autumn, because there was no pile of tubers on the top to protect lower ones. The ones I left in place, I lost only a few and that could have been voles eating the tubers from the evidence.
I think you will get atleast a few blooms from your new dahlias before frost...enough to see how you like them.