Hormone imbalance and heat fluctuations linked to deformed flowers
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This About Face grandiflora rose is displaying
fasciation in its spent bloom. (Photo: Debbie
Arrington)
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They look like something out of “Little Shop of Horrors”: Weirdly distorted buds that sprout out of the center of a spent rose. And this summer, more seem to be popping up on rose bushes throughout Sacramento – as well as other plants.
It’s another garden oddity likely tied to extreme fluctuations in temperature: Fasciation.
This phenomenon – strange, unexpected growth of terminal buds – is a genetic mutation of a plant’s growing tip. It’s believed to be triggered by a hormone imbalance that may be caused by outside factors such as roller-coaster temperatures or exposure to herbicides (such as Roundup).
I can’t help it; I’m fascinated by fasciation. In roses, it looks like a whole spray of monstrous buds is trying to wiggle out of the center of a bloom – often before the first flower has dropped its petals.
I have one hybrid tea – Perfect Moment – that always seems to display some fasciation in the heat of summer (and it did). But this August, I’m also seeing fasciation on bushes that never showed it before. That includes About Face, a very tall grandiflora; this week, several of its spent blooms sprouted the weird deformed buds.
The roses were not exposed to Roundup or other chemicals; it had to be the heat.
The good news: It’s not contagious. Snip off the weird flower and the plant will (fingers crossed) grow a “normal” bud.
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Fasciation also can show up in sunflowers. This was a
bloom that exhibited some weird extra growth. (Photo: Kathy
Morrison)
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In strawberries, fasciation creates giant double or triple berries. The cockscomb celosia – with flowers that look like rooster heads – are a result of fasciation.
Heirloom tomatoes – particularly those with ugly bottoms – are believed to be another case of fasciation as a desirable trait.
Fasciation also can produce flat, fused stems or tufts of fused growth, often referred to as “witches’ broom.” Besides heat and herbicides, fasciation may be caused by bacteria, in particular Rhodococcus fascians , say UC master gardeners.
For more on fasciation: http://ipm.ucanr.edu/PMG/GARDEN/FLOWERS/DISEASE/fasciation.html
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Garden Checklist for week of Jan. 19
Dress warmly in layers – and get to work:
* Apply horticultural oil to fruit trees to control scale, mites and aphids. Oils need 24 hours of dry weather after application to be effective.
* This is also the time to spray a copper-based oil to peach and nectarine trees to fight leaf curl. The safest effective fungicides available for backyard trees are copper soap -- aka copper octanoate -- or copper ammonium, a fixed copper fungicide. Apply either of these copper products with 1% horticultural oil to increase effectiveness.
* Prune, prune, prune. Now is the time to cut back most deciduous trees and shrubs. The exceptions are spring-flowering shrubs such as lilacs.
* Now is the time to prune fruit trees. Clean up leaves and debris around the trees to prevent the spread of disease. (The exceptions are apricot and cherry trees, which are susceptible to a fungus that causes dieback if pruned now. Save those until summer.)
* Prune roses, even if they’re still trying to bloom. Strip off any remaining leaves, so the bush will be able to put out new growth in early spring.
* Clean up leaves and debris around your newly pruned roses and shrubs. Put down fresh mulch or bark to keep roots cozy.
* When forced bulbs sprout, move them to a cool, bright window. Give them a quarter turn each day so the stems will grow straight.
* Browse through seed catalogs and start making plans for spring and summer.
* Divide daylilies, Shasta daisies and other perennials.
* Cut back and divide chrysanthemums.
* Plant bare-root roses, trees and shrubs.
* Transplant pansies, violas, calendulas, English daisies, snapdragons and fairy primroses.
* In the vegetable garden, plant fava beans, head lettuce, mustard, onion sets, radicchio and radishes.
* Plant bare-root asparagus and root divisions of rhubarb.
* In the bulb department, plant callas, anemones, ranunculus and gladioli for bloom from late spring into summer.
* Plant blooming azaleas, camellias and rhododendrons. If you’re shopping for these beautiful landscape plants, you can now find them in full flower at local nurseries.
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