First Time Growing Dahlias

15 years ago

Hi all, I have been a gardener for too many years to remember, but this is the first time I have attempted to grow dahlias. I have raised wood-sided bins for my vegetables and this year I planted two bins with dahlias (got them at Costco) - experts please don't cringe - it was a spur of the moment purchase. I got two packs of the tall variety and one of the shorter versions. My bins have ground cover cloth and bark over that to help retain moisture - very hot and drying winds here most of the time.

All of the bulbs came up but two - unfortunately I was going to label each plant with markers but the plastic labels faded in the sun and now I can't read them - so much for good intensions.

I have a few questions. I just read somewhere that dahlias need some shade from the hottest of climates and our summers get over 100 routinely and being in raised beds I am sure the soil will dry out more rapidly. I was thinking of putting up solar fabric on the west side of the bin to shade them in the afternoon? What do you think?

Some of the dahlias have deformed new growth (actually hardly any leaf just the stem portion of the leaf) and I can't tell if this is from our late frost on 4/21, grasshopper damage, a virus or some thrips. We did have quite a few grasshoppers, but the damage seems too regular to be from grasshoppers.

Oh I forgot at the beginning of their growth there was a black aphid invasion and I sprayed them with a garden bug spray because I just couldn't get rid of the darn aphids by spraying with insecticidal soap or spraying with a vigorous spray of water. could the garden bug spray have been too strong for the leaves?

I will take a photo of the leaves tomorrow morning and post it. I can't see any other insects and other plants in the bin (bee balm) don't have any damage except an occasional hole or two probably from the grasshoppers.

What about fertilizer? I have some 10, 15, 20 and gave them a half dose about a week ago? Should I continue with that?

The dahlias which are doing well are now putting on buds - can't wait to see what the blossoms look like.

I have them staked up with some extra tomatoe baskets I had. We get quite a bit of wind here too so I didn't want them to fall over. I think they are going to get larger than the baskets though. So I will probably have to come up with another staking method soon.

Any advice is appreciated. I'll post a photo of the damaged leaves early am tomorrow.

Linda

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Comments (7)

lattefairy
15 years ago
"I just read somewhere that dahlias need some shade from the hottest of climates and our summers get over 100 routinely and being in raised beds I am sure the soil will dry out more rapidly."

Last summer we had lots of 100F days -and very low humidity-and mine grew beautifully in FULL sun, getting that scorching afternoon heat and all. On the worst days, I'd just water them late afternoon and that has always been plenty. I had the most beautiful dinnerplate dahlias till frost. :)

"What about fertilizer? I have some 10, 15, 20 and gave them a half dose about a week ago? Should I continue with that?"

I don't add fertilizer to mine. Just a nice layer of compost seems to do the trick.
bluestarrgallery
Original Author
15 years ago
First photo is a dahlia with normal leaves and second one shows the deformed leaves. Also the deformed leaves are lighter green - any thoughts?

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bluestarrgallery
Original Author
15 years ago
lattefairy, in summer I water my bins every late afternoon so the plants can take up water during the night, so I guess I will do that with the dahlias too. Since they are in raised bins the water drains away quickly.

Two years ago we had three days of 118 and two weeks over 105 - all the plants suffered that year. I hope we don't have that this year. Last week we had 105 and this week 72 - the weather is wacky. If I hear about a heat wave I might put up that cloth, if not it would be easier not to have to build a temporary structure to staple the cloth to.

Thx.
lattefairy
15 years ago
"lattefairy, in summer I water my bins every late afternoon so the plants can take up water during the night, so I guess I will do that with the dahlias too. Since they are in raised bins the water drains away quickly."

Yeah, that should work. If you apply a layer of compost to the surface, it'll help with moisture retention and a more even soil temperature.

About the deformed leaves, that looks to me like a symptom of disease.
bluestarrgallery
Original Author
15 years ago
lattefairy, I was afraid someone was going to say disease. I looked up a link on this site about dahlia diseases and it didnt' look like anything they showed. I wonder if the frost could have damaged the tissue somehow - I keep hoping they will come out of it. I may check with the farm advisor or extension agent and see if they have a clue. I was so looking forward to some big beautiful blossoms, but even the buds are affected with the same stunted deformed look to them. Boo Hoo !
bluestarrgallery
Original Author
15 years ago
I found out grasshoppers were eating my dahlia leaves, apparently they love them. Will post photos of the flowers I have so far in another post.
lattefairy
15 years ago
Good to hear that you've found the culprit! :)