Q.
We have two 12-year-old Texas Sage shrubs concealing the street mailboxes.
Within a month this past summer, they were dying back rapidly. The dieback spread
over both plants. The irrigation hasn’t changed. Any idea what could be causing
this?
 |
| Not readers plant. Showing collar rot. The top dies because its choked….rotten. |
A.
My explanation follows the KISS principle. Texas Sage, a Chihuahuan desert
native, has roots that die if watered too often. If the main stem or trunk of
this shrub stays wet, this could cause it to die. My guess this is a trunk/root
disease caused by watering too often. This disease moves with irrigation water
and can spread easily between nearby plants.
Put Emitters Close When First Planted
When first planted, the drip emitters must
be close to the plant. I like to put them up to about 12 inches during the first year. They should be moved, and more drip emitters added, as
the plant gets larger in the second or third year. They are moved to about 12 to 18 inches away from the trunk at this time. This practice does not change the irrigation frequency
but changes how much water is applied and where it is applied. A larger area
under the plant is watered to compensate for its increased size.
Move the drip emitters away from the
trunk or main stem to a distance of 12 to 18 inches from its trunk. This should be done
when the shrub is 2 to 4 years in the ground. At the same time, add more drip emitters
and redistribute the emitters so that they irrigate half the area under the enlarged
plant canopy. This gives the plant more water, distributes the water to a
larger area because it’s larger and reduces the chance of trunk/root diseases
of susceptible plants.