Mighty Oaks Need Tender Loving Care
Landscape under oaks by not landscaping under oaks
By Dale Norrington, Master Gardener
Although
seemingly invincible, established oaks are often quite sensitive to
environmental changes which occur as we landscape under and around them. Care may be taken to avoid allowing beautiful
landscapes to lead to stress, disease, failure, or death of the stately
sovereigns they were meant to complement.
A
critical zone exists around an oak which should remain undisturbed. Commonly referred to as the root zone, it
extends around the tree from trunk to drip line and beyond, to a point roughly
half again the distance from the trunk to the drip line. The natural condition of this area should be
retained as much as possible.
Avoid
installation of paving, or use of heavy equipment or vehicles which could
compact the soil. Do not raise or lower
the natural grade in this area. Do not
pile up soil around the trunk of the tree.
Allow fallen leaves to remain in place.
Minimize
planting in the root zone area. Avoid
use of groundcovers, or other plants with extensive root systems. Do not plant a lawn beneath an oak. If planting must occur, restrict it to use of
a few accent plants, and choose varieties which do not require more than a
relatively deep, monthly irrigation during summer. Avoid any other irrigation, and do not wet
the crown of the oak, or the area in the immediate vicinity of the crown. Choose fire resistant varieties, and restrict
their height to minimize the potential for fire to move from them into the
branches of the oak.
Oaks
may be pruned during late winter and early spring. Dead, diseased, or injured branches may be
removed. Lower branches and foliage may
be removed to a height of ten feet for fire safety, and interior foliage may be
removed to afford views through and beyond the tree, and to expose the bold,
gnarled texture of the limbs. It is
generally best not to top an oak, or to stub its branches. Remove no more than 10 - 20 per cent of total
foliage each season.