Was Your Arizona Tree Planted Too Deep?
A tree can remain alive for years while never looking quite right. Growth stays slow, the canopy seems thin and small branches die without an obvious reason. Homeowners may add fertilizer or increase the watering, yet nothing really changes. In many cases, the problem began on the day the tree was planted.
An Arizona tree planted too deep has trunk tissue buried beneath soil, decorative rock or mulch. That tissue is meant to remain above ground where it can stay dry and receive air. October is a useful time to inspect the base of a tree because cooler weather makes landscape work easier and many Arizona homeowners are preparing for fall planting.
Look for the Root Flare
A healthy tree trunk should widen where it enters the ground. This widened area is called the root flare. The first major roots begin there and spread outward from the trunk. Both the University of Arizona and International Society of Arboriculture recommend keeping the flare visible at the finished soil level.
When a trunk disappears into the soil like a straight post, the flare may be buried. Scrape aside loose gravel or mulch carefully and see whether the trunk begins to widen. Do not dig deeply with a shovel or cut roots simply to investigate. The purpose is to identify the visible planting level, not perform an excavation without knowing what lies beneath.
How Trees Become Buried Too Deeply
Some trees are placed too low in the original planting hole. Others arrive from a nursery with extra soil covering the top of the root ball. Soil may also be added later during grading, installation of decorative rock or changes to nearby beds.
Mulch piled against a trunk creates a similar problem. It holds moisture against bark and hides the proper base of the tree. A neat looking mound can therefore cover an unhealthy condition. The International Society of Arboriculture recommends leaving a mulch free area immediately around the trunk.
Warning Signs Above and Below Ground
A buried root flare may contribute to slow growth, sparse foliage, dead branches and general decline. Constant moisture against trunk bark can encourage decay. Roots may also begin circling close to the trunk rather than growing outward into the surrounding soil.
As circling roots enlarge, they can press against the trunk or other roots. This is known as girdling. The restriction may interfere with the movement of water and nutrients and weaken the tree over time. A tree with serious root defects may also have poorer anchorage during strong winds.
These symptoms can have other causes, including irrigation trouble, compacted soil, pests and disease. The appearance of a straight trunk alone is a reason to investigate, not proof that the tree is beyond saving.
Do Not Simply Add More Water
A struggling tree often receives extra irrigation, but that may worsen conditions when soil already covers the trunk. Water should be applied across the active root zone, not concentrated against the bark.
Likewise, fertilizer will not correct improper planting depth. Before treating a declining tree, identify the physical condition of the root flare and surrounding soil. Correct diagnosis can prevent money being spent on treatments that do not address the real problem.
Can a Buried Root Flare Be Corrected?
Shallow excess mulch or loose soil may be removed carefully by hand. A deeply buried flare is a different matter. Excavation can expose decayed tissue, circling roots or structural problems that need professional judgement. Large roots should never be cut casually because they may be important to stability and water uptake.
A certified arborist can determine where the true flare begins, assess the root pattern and recommend a sensible correction. Some trees respond well once excess soil is removed. Others may need root management, improved irrigation or monitoring for decline.
Have the Base of Your Tree Assessed
Liberty Tree Experts takes a complete view of tree health, including planting depth, soil, irrigation and structural condition. For professional tree assessments in Scottsdale, Mesa, Tempe and communities across the Phoenix Valley, call (480) 482-9374. A certified arborist can inspect the root flare and explain what should be corrected before a hidden planting problem becomes a larger expense.
Live References
University of Arizona: Planting Guidelines for Container Trees and Shrubs
International Society of Arboriculture: Planting a Tree
University of Arizona: Choosing the Right Plants