My 65' X 15' shrub bed has a dozen shrubs in it. When they were planted from 1 gal. pots, the 1/8" drip hose was sufficient. Now they are mature shrubs ranging from 5' in diameter to 10' in diam. No longer is that water sufficient. I have read that roots can go up to 3 times the diameter of the crown. Other than hand watering, how should I expand my irrigation system to accommodate their mature size? Plants include 3 dogwood bushes, a nashiki willow, caryopteris, tamarisk tree, 2 weigelas, star magnolia, mugho pine, callicarpa, and smoke bush, all in 2 rows. I have landscape fabric with rocks over it between the shrubs, and a red shale path. Should I just add pop up lawn sprinklers to broadcast the water everywhere? I can't do drip irrigation to the 4 corners of each shrub when I don't know where the roots have expanded to.
expanding shrub roots