CO-Horts Blog

Tuesday, July 9, 2019

A wet, cool year isn't always good news for gardens

A wet, cool year isn't always good news for gardens

Darrin Parmenter

If you live in the southwest corner of the state and still read a newspaper, you may have noticed that our climate and/or environment tend to be pretty common topics (as does my use of parenthesis). But really, as gardeners, or farmers, or landowners, so much of our success is based off of: a) if Mother Nature is nice or naughty; or b) how we adjust for her naughtiness without making her more upset. 

2019 is one of those years – nice and well, the consequences of that kindness. Yes, snowpack was amazing this past winter and spring. Snow is still melting, rivers and creeks are still running high, and reservoirs are continuing to fill at a very quick rate (and it’s the first week of July! And I’m using more parenthesis!). 

But along with all that moisture came a relatively cool and wet spring and early summer. The high temperatures in May were 7 degrees cooler than normal; in June, they were 4 degrees cooler. Many of you experienced a frost (or even a freeze) on June 23rd. During the last week of June we had an average daily temperature difference of 36 degrees. So after a couple cold nights, our tender annuals and vegetable that survived the frost have had a tough time getting going again.

You know what else came with the all this winter and spring moisture, cooler than normal temperatures, and higher than normal relative humidity? Telephone calls, emails, samples, site visits, and photos. 

If you like plant diseases, insects (and I do) and weeds (I don’t), well, 2019 is your year. We started with carpets of purple mustard (Chorispora tenella) that blankets our fields and then moved onto that relatively rare, and eventually annoying, mountain cicada (Okanagana bella).

They do little or no harm to your plants (although we have witnessed some wounding by females laying eggs in soft-wooded trees and shrubs) even though they are one of the larger insects you will find in Colorado. Apparently, they emerge every 3-5 years, however this is the first time I remember seeing them, and I’m old. What we are hearing are males trying to attract females.

Aphids and thrips have also been impressive this year, and while aphids are not uncommon in our annuals, perennials, and trees, thrips in the garden 
(and not just in the annuals that come from greenhouses) are relatively rare and unfortunately tough to control. Try insecticidal soaps – or a jet stream of water from the hose – to keep numbers down. Just know that both insects lay a lot of eggs and can also utilize a form of asexual reproduction called parthenogenesis in which an adult female can lay an unfertilized egg to develop into a genetically identical female offspring.

Because of our low relative humidity and the fact that we have a cold winter, fungus and bacteria are typically not an issue. But guess what? Not this year! I’ve seen bacterial issues on tomatoes, peppers, and even landscape ornamentals. Cedar-apple rust is showed up as orange globs in the junipers this spring and can potentially harm our apples, pears, hawthorns and other plants in the rose family. When you see those gelatinous masses in the trees, prune them out and stop the cycle. 


And lastly, and probably most impressively, I just got a photo of slime mold which was awesome! Also known as “Dog Vomit Fungus”, this mass (about 1 foot wide and 1 foot tall) probably formed where there was a lot of moisture. They don’t cause any problems, but sure are attractive to kids with sticks or fingers or adults with weed whackers (or sticks or fingers). Or so I’m told…

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