Dead green ash trees (July 2013)

All through our (usually) dry winters, we’ve been beating the drum to get people to winter water their turf AND their trees. With our ongoing drought and irrigation restrictions, we find ourselves in the surprising position of having to remind people to “summer water” their trees.

Most of the trees in our area have been introduced and can have a tough time thriving even when we are not in drought. After several consecutive years of drought, super late hard freezes this year, and watering restrictions, our trees are having a tougher time than ever surviving. Many trees that have been on the edge of survival for the past few years have finally died this year and others are very close (like those trees in the downtown medians with about a quarter of their normal leaf cover).

Often sources say that trees can store up to three years worth of energy to get through tough times. Unfortunately, our trees have used up those reserves. According to local arborist, Becky Wegner, any mature tree you see without leaves right now is gone; they will not draw on reserves to try to leaf out next year.

Trees need deep soakings throughout the area from trunk to dripline (draw a line down from where the branches end to the ground and you’ll have the dripline) at least once a month – more so when we’re in drought. This can be tough during watering restrictions; you can’t put a sprinkler out on your non-watering days. However, wrapping a good long soaker hose or two around the area under the tree is a great way to water, and you can do that at any time under our watering restrictions. How much to water? Until you have gotten the top twelve inches of the soil wet (yes, you’ll need to dig to check).

Many homeowners prioritize watering their lawns during watering restrictions (and even when NOT under restrictions). However, consider how long it will take to replace a large, mature tree versus how long it takes to repair brown patches in lawns. Trees are much larger investments and much more difficult and expensive to replace!

For more details on how to care for your trees during drought, see this excellent page from Colorado State University Extension: Caring for Trees in a Dry Climate

Contributed by Carey Harrington, Certified Colorado Gardener and Colorado Native Plant Master