Wednesday, May 20, 2020

Poor Leafing Out - What's the Deal?





Mini Man Viburnum didn't mind the April Cold Snap
For some reason after I took down this post temporarily, Google Blogger decided to send you a December '19 blog about seed starting. I have no idea what happened. Here is the blog again about plant loss from the April flash freeze. A longer, enhanced version was recently published in The Denver Post.

My two-year old bloomerang lilac shrub looks half dead, or should I say half alive. The five bloom clusters look sad and are asking - "where's the rest of my leaves, I feel naked, am I dead?"
Half Alive Bloomerang Lilac Small Shrub

Other gardeners are describing similar leafing out delays and plant concerns.

What's up with our plants this season?

It's the weather, Wanda (insert your name here).

What we know - Colorado spring weather is often a series of extreme see-saw warm-cold-snow-hot (any order) from March through May. Described in wardrobe choices - shorts in the am, fleece at noon, rain parka from two to six pm, back to shorts at seven. Coloradans never move their winter gear to the back of the closet.

What happened - April 2020 was one for the books in more ways than one. We were sheltered indoors due to COVID-19 and at the same time, eighty plus year old record temperature lows took place in the middle of our spring buzz. Here are the facts with a little context.

March 2020 was warmer than average. Moving into April, seven out of the first eleven days were in the low seventies. All kinds of trees and shrubs were steadily trotting along ready to flower and leaf out for the new season. But no ... spring can't be this easy along the Front Range and plants never forget past extreme weather swings. Those events contribute to the present state of plant health.

Bold cold temperatures stopped spring in her tracks over the second weekend of April 11, 12, 13. The chill was felt by everyone, more so for our plants. Days in the 20s to low 30s, nights got as low as 11 degrees. Brrr, and no bloom for you, period, end of story. 

The April freeze flash caused plants to just stop in mid-trot and accept the cold and the damage that was to come. Injured plants don't always look or act the same. In addition to browning out (boxwood below), there can be delayed leafing out or in the case of my lilac, death to certain branches on the shrub.

Cold Damage on Boxwood shrubs (not mine)
Add to the delayed/damaged list a friend's hydrangeas, redbud trees, boxwood shrubs, roses and many more plants felt the cold - literally smack dab in the canopy! Our silver lace vines still look they look all winter - barren, brown climbing sticks. I'm just starting to see a little growth at the base. Conifer trees in many areas along the Front Range didn't take the cold well and showed their discontent with brown tips, mostly on their north sides. 

The garden glass is by no means half empty dear gardeners. Many plants breezed through the April cold blip just fine. Our Mini-Man Viburnum Plant Select shrub stood proud, as did the Goldhill golden aster and many more. The lawn was fine.

What can We do? Accept that weather affects plant health. Technically the half dead lilac wasn't well established, so my guess is part of the shrub just couldn't gut out the cold. The Miss Kim lilac growing not far from the bloomerang is fine and is just beginning to bloom. Redbud trees are pushing new leaves as I write this post. I've read from reputable tree care professionals that conifers often grow out of the damage. We need to allow time for plants to recover, some plants have been around longer than us and they'll do the best they can to leaf and live.

Remember though, dead is dead, so any branches you see that aren't leafed out and are brittle when snapped are probably gonners. Dead and damaged branches can be pruned any time of the year. The exception are fruit trees; it's best to prune them in late winter before the buds break to flower. The dreaded fire blight disease is always of concern in spring.
 
Additional reading on spring cold and plants -




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