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Bloom Color Variation in Weather

Posted by ArbutusOmnedo 10/24 (My Page) on
Thu, Apr 3, 14 at 1:17

I often read that blooms take on different shades in cool versus hot temperatures. What temperatures would fall into the cool and hot ranges respectively? Or rather what is the cutoff from cool to hot weather as far as rose bloom coloration is concerned? (I'm going to be using Farenheit temperatures).

Southern California is largely pegged as very warm and dry, but Santa Monica is relatively cool and humid because of coastal influences. Summer temps are seldom higher than the low 80s, but usually somewhere in the 70s. Late summer and early fall are the warmest times, "winter" is a little cooler and frostless, and Spring might be the coldest average time here.

Would I tend to almost always see what many growers refer to as "cool weather blooms" (given the same sun exposure)? I've never felt very clear about that, since all seasonal climates vary and most places are much less temperate than here.


Follow-Up Postings:

RE: Bloom Color Variation in Weather

My guess is that if your temps are rarely above the 80s, then you will probably see mostly the cooler weather colors.

Here in Kansas, our hot weather is in the 90s and 100s--sometimes for most of the summer or nearly 2 months out of the summer. When the temps drop to 80s, we definitely experience that as "cooler"!

In other words, in your part of the country, my HT Elle would probably be fuller colored and my HT Double Delight might never get to its full beauty since its distinctive coloring requires more heat.

But change of coloring might actually be more complex than just considering the temps--other variables that also affect coloration.


RE: Bloom Color Variation in Weather

  • Posted by seil z6b MI (My Page) on
    Thu, Apr 3, 14 at 12:04

Temps in the 70s and 80s are what I would call average. High temps would be 90s and 100s and lows 60s and below..

For me high temps are 90s and up that we get in July and August. The roses tend to be paler in color but not all of them. There are a few that actually get brighter in hot weather. Cooler temps are 60 and below. And not necessarily daytime temps but the night temps which begin to dip down into the 50s and 60s in late August and September. The colors can get deeper and/or brighter then. However, when it starts getting much colder, like 30s and 40s, they get pale again. Of course that could also be due to the reduced sunlight as it gets later in the season.

RE: Bloom Color Variation in Weather

Because I got addicted to taking pictures of my roses in 2013, I had several comparison pictures. I didn't set out to notice the differences, but when I began looking at the pictures I had taken, the differences were obvious. Wish I knew how to put the pics side by side.

Tiffany on August 12th. The temperature range was probably in the high 80's to low 90's

RE: Bloom Color Variation in Weather

Tiffany on October 29th. Temperature ranges in the high 50's - low 60's.

RE: Bloom Color Variation in Weather

  • Posted by curdle 9b, Australia (My Page) on
    Sun, Apr 6, 14 at 8:41

I think colour in roses also has to do with intensity/quality of light, as well as the heat ( and especially so for roses like Double Delight). during the month of heatwaves we had this summer, I moved a lot of potted roses under the carport; not the best as they didnt get any direct sunlight, but better than them frying. Just Joey went into summer colouration mode (pale delicate salmon), but Double Delight produced a few cool weather blooms (creamy white, with barely any red at all).

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