The elusive Northwest Summer season may have arrived this week, as we all know it should, immediately on the 5th of July. Now that some warmer weather may be here to stay, we should consider the effect it has on our landscapes, especially any newly planted trees.
Most all of our customers follow our irrigation and watering instructions to a tee, but there are always a few folks who decide they are going to remember to water their trees by hand, and decide they do not need any automated timers or systems in place. Now, I’m not sure how many folks go this route with no ill effects, but I do know that most every person who calls in experiencing some Summer difficulties with their trees has gone the manual irrigation route, and readily admits to missing a few intervals of watering. Sometimes these well meaning folks make comments to the effect of how there has been a lot of rain this season and it didn’t seem necessary.
Unfortunately, the rains we receive in this part of the country are so quickly absorbed and drained away by our soils, that even when the weather seems wet the newly planted trees are just getting by at best. Many times, people will notice that the root ball surface under the tree is dry, as the canopy of the tree sheds the water out and away from the root ball. This is why automated, consistent drip irrigation is so necessary to the successful transplanting of a tree. When the water is getting to the root ball, the problems associated with tree transplanting are eliminated.
Most of the time, drip irrigation delivery systems like soaker hoses and perforated plastic tubing can be set for 15 to 20 minutes, every other day when the temperatures are below 70 degrees. Once the daily high temps start sneaking up to 80 degrees, many times it is wise to set your timer to deliver the same amount once a day.
Now then, these suggestions are just that, suggestions. The only way to be certain that your trees are getting ‘enough/not too much’ water is to dig a hole 6 inches deep next to the root ball of the planted tree. Try and do this moisture test around 4 hrs after the drip system last operated. When you take this soil and ‘snowball’ it with your fist, it should hold its shape and feel damp. If the soil is dripping water as you squeeze it, there is too much watering going on and you need to throttle back with the timer. If the soil is dusty and falls apart in your opened fist, you are going to need to turn up the water until it looks good and damp at a later test time.
It never hurts to keep an eye out for old and existing trees in your landscape as well. If we actually get hot, sustained temperatures some older trees can suffer as well. A little water can go a long way to keeping older trees happy, and eliminate some die back of foliage and branches. If people and the news stations are talking about the heat, make sure to water the older trees once a week for a few minutes. If you drizzle a swirl of liquid dish washing soap over the obvious root area of the large tree, you will see an immediate difference in how much water will be absorbed vs. shed down the slope. It’s a fun trick to see in action if you haven’t before.
Hopefully this is all useful advice regarding the watering of new and existing trees. Now if we could just figure out a neat way to keep handy all the layers of clothing necessary for our NW Summers…