Blooms lost to cold

Some plants lose their flower buds to the cold during winter. Sometimes we can see this long before bloom season and be better prepared at the loss of show. We might also prune a spring blooming shrub differently when we know it's not going to be contributing to the spring show.LilacBudOnly0651.jpg


We've shown you how to look into the bud of a lilac or a forsythia to see if flowers are there. Here are a few more examples of such sneak peeks:


Kousa dogwood

Darn, its flower buds are drying up and turning brown.


We sampled buds from several areas of the canopy and found only buds in this condition, so we think all or most of this dogwood's blooms are kaput.

This tree, like many kousas in our area, held onto its leaves last fall. (For more about that, see Leaves hung on.) That can indicate that a tree was caught short -- not yet finished with the living process of leaf drop and perhaps also still working on hardening off when winter descended, killing the leaves while still attached.

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So we won't say it was only the cold that blasted the blooms. Perhaps it was the cold in addition to the plant's lack of readiness. Given a fall that progresses more gradually, the tree may be able to handle cold equal to what it felt this winter, without losing its bloom.

But this year, we will not expect flowers. We will also thank the garden gods for leaf tissue that's hardier than flower petals, even in bud. What a setback it would be for the tree to have to replace all those leaves.

We may also do some extra watering and fertilizing in this tree's root zone, with the hope of speedier growth. That's because all those unclosed openings at the bases of last year's leaves and the dead flower tissue at the tip of the new shoots may offer leaf spot fungi an easy opening. The more rapidly the tree's new growth matures and harden, the more resistant it will be to infection.

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Cherry flowers form on spurs -- short side shoots off mature wood. The straight twig at the bottom of the photo (right), has no spurs. We removed and sliced open buds from the spurs (below, magnified 10x)  to check the condition of the flowers.


We sampled buds from several branches on the most protected weeping cherry we know and found that nine out of ten contained the same dark, decaying mass where a flower should be. Ah, well! We can hope our State's fruit cherry crop fares better; those trees are genetically different.




The big central bud is the rhodie's flower bud. Subtending it (arrows, photo at right) are the buds that will be the new branches and leaves.

Most of the rhodies in our area took a severe a hit from the cold. They lost or will lose many leaves. This setback hit our local plants even harder since most were only marginally healthy to begin with in the Midwest's alkaline soil and dry air.

The plants' distress caused us to plan to snap off the flower buds this year. We think a year without blossoms (they'd look wrong above such bedraggled plants! ) is acceptable and hope the flowering  energy will be diverted to the plant's overall recovery.


We'll also prune back hard on some of these plants, to stimulate foliage development lower and in the interior. (See Deciding what to cut.)RhodoProtctd7953s.jpg

(Just an aside here: People have occasionally prefaced conversation with us, "We know you don't like rhododendrons..."
We'd like to put that rumor to rest. We both love rhodies. We simply don't like to see them grown in unsuitable places, and bragged on by people who seem unaware that the plants could be so much more.)

Silver lining: Here and there rhododendrons did pull through with little harm (below). Now we are certain of the value of all that extra attention: Finding them protected places, fertilizing and watering specially so they could be dense and healthy enough to weather winter's worst.



Plants with other reasons to forgo bloom

Sometimes trees and shrubs take a year off after a very heavy seed production. So much of the plant's energy in that year goes into the fruit that few flower buds develop.


It's likely that redbud (Cercis canadensis, right, still loaded with seed), apples and crabapples may sit this one out or bloom very lightly, having delivered record breaking crops last fall.

Note the bare branches above the redbud's seedy limbs. Most of that is last year's new growth, produced post-bloom. Redbud is a plant that lives up to its reputation for fast growth, even in a banner year for seed.