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How much sun for dahlias is ideal?

Posted by HighlanderNorth North DE (My Page) on
Tue, Jun 12, 12 at 14:20

I was originally told that dahlias need lots of sun. Then I was told by Swan Island and read that dahlias need AT LEAST 8 hours of direct sunlight each day, or more, or they will NOT grow well, and wont flower well.

Then last year I found the only relatively sunny spot on our 1.3 acre wooded property and planted them there. At first, in late May/early June when I first planted the dormant tubers in the ground, and also at the time of year that the sun is highest in the sky, it seemed my dahlias would get between 6-8 hours per day of sun, depending upon which spot each was in.

They were surrounded by high trees, with a large hole that created a clearing. But once the season progressed, and the sun started going back down in the sky starting in August, the amount of daily sun my dahlias got began to decrease fairly rapidly.

By mid September, they were only getting between 4-5 hours per day depending on what spot each was in, but by mid to
late October it was down to like 2-4 hours per day, or less.

So, when they were doing their vegetative growing, they got a pretty good amount of sun, but some still had less than 8 hours. But when actively blooming in September and October, they were getting much less than 8 hours, but they bloomed from start to finish in early November very well. I didnt see any signs that the lack of sun was effecting their blooming. In fact, 2 of them were just starting to produce another glut of flowers right when the first hard frost hit and killed them back. They did grow taller than advertised as a result of a lack of sun, but they bloomed well.

This year, I have moved and I'm growing them all in decent size pots, and I have about 27 plants right now, of 17 varieties. The area where they will be growing gets about exactly 8 hours of sun, and when the sun starts to drop, I can move them to a sunnier spot.

So, whats the truth about how much sun is ideal for dahlias, or how much is the least they can tolerate while still blooming well?

Whats the least amount of sun you've been able to successfully grow dahlias under, while still getting good blooming?

Follow-Up Postings:

RE: How much sun for dahlias is ideal?

New to Dahlias so looking forward to seeing responses.

RE: How much sun for dahlias is ideal?

Hope you're not in a hurry, as it may take a while!

RE: How much sun for dahlias is ideal?

I suspect you are not getting any answers because you are looking for a definitive answer for something not easy to define.

Meaning (and this is my 2 cents worth) - dahlias are both finicky and yet they are adaptive to their known environment. That is only how I can explain my garden full of flowers when we have summers where you may not see the sun for months. Granted, sun can filter thru fog anyway but my dahlias that have been in the yard a year or more tend to get better with age and have adapted to the fact that the ground is almost permanently moist from fog, the dahlias get so wet the larger ones tend to fall over and the sun (on good days) shines only about 5-6 hours.

I have found that when they get a good dose of sun daily (like this spectacular year) they tend to wilt after blooming. So I have deduced they have adapted to their conditions and have learned to prosper even during 60 straight foggy days, like last year.

This year, I planted 6 dahlias in the shadiest part of the yard and so far 5 have sprouted, one is almost blooming and one is MIA so far. This part of the yard gets about 4 hours of direct sun on a good day and they seem to be doing fine anyway.

In a nutshell, despite what growers tell you, I think dahlias can do fine without 8 hours of sunlight. My yard in August can prove it.

RE: How much sun for dahlias is ideal?

Swans Island says 8 hours is best.

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