Summer Tree Care

Tree with houses in the background
Summer tree care helps landscape trees look great all season.

Trees are the ultimate givers, offering summer shade, protection from wind, and cleaner air.  They also beautify our landscapes, often providing food and serving as habitats for wildlife.  But, even in the face of all that generosity, we often ignore them.  Our trees deserve better, and summer is a good time to turn over a new leaf and focus on tree care.

Summer weather stresses trees.  Drought is hardest on very young or old specimens but ultimately affects them all.  Storms threaten stability and bring weak or diseased limbs crashing to the ground.  Lawn and garden equipment damages tree bark, while untreated pests and diseases can decimate entire communities of once-healthy trees.  Fortunately, it takes only a little observation and a bit of care to help trees withstand those stresses, enabling them to continue giving for decades to come.

Inspect Your Summer Trees

Tree with white blossoms
Healthy trees will have vibrant foliage, growth, flowers, and fruit.

Start by taking a good look at all the trees on your property, using binoculars, if necessary, for large trees.  Check for limbs that are dead, cracked or otherwise compromised.  If damaged trees are large or need anything more than minor pruning, call a tree expert to perform the work.  This may seem expensive, but corrective pruning helps trees withstand summer windstorms and prevents potential property damage and personal injury caused by falling limbs.

 Check Trees for Pests and Diseases

Tent caterpillars on the upper branches of a black cherry tree
Tent caterpillars on the upper branches of a black cherry tree.

If you seek expert advice or help with pruning, ask an arborist or tree surgeon to check for pests and diseases.  Pernicious pests like the emerald ash borer and the Asian long horned beetle can wreak wide-scale havoc, killing scores of trees in a single area, if infestations aren’t promptly controlled.  Bag worms, fall webworms, and early season tent caterpillars can cause significant damage to foliage, which stresses trees. Wasting diseases, like verticillium wilt in maples, can sometimes be arrested, if affected trees are treated in time.

If you don’t have expert help, check with your local cooperative extension agent to find out which pests and diseases are most prevalent in your area. Some municipalities employ professional arborists who can also provide this information. Take a good look at tree bark and foliage for telltale problem signs.  Follow the expert’s advice on treatment or prevention of pest or disease outbreaks.

Water Summer Trees Wisely

Silver watering can
Summer tree irrigation is especially important for newly planted trees.

All trees need regular water, though mature specimens, with broad, healthy root systems are best able to tolerate extended droughts.  Young trees are a different story and need water every few days if rainfall is sparse or nonexistent.  The best way to water tree roots is low and slow irrigation, positioning the water source close to the ground.  This means soaker hoses circling trees’ bases.  For newly planted and very young trees, property owners can also buy “tree bags”, water-holding, heavy-duty plastic bags constructed to wrap around the trunk.  Small holes in the bottoms of the bags allow water to seep slowly to the roots, a process that takes several hours, depending on the size of the bag.  Refilled every day or two during drought spells, the bags can be lifesavers for immature trees.

Protect Trees from Mechanical Injury

Tree rings with wheelbarrow
Tree rings protect trunks from mechanical injury, but beware “mulch volcanos”!

Power string trimmers are great garden time savers, allowing landscapers and homeowners to keep bed edges neat and tidy.  But repeated blows to trees from trimmers can penetrate tree bark to the point where young trees may die.  Trimmer injuries may not kill older specimens outright, but create entry points for damaging pests and diseases.

The best way to separate trimmers and tree trunks are to mulch tree rings around trees, a technique that also conserves soil moisture and keeps weeds under control.  Spread high-quality mulch in a circle with a radius of at least 2 feet around the base of the tree.  Keep the depth at about two to three inches and do not let the mulch touch the trunk.  So-called “mulch volcanos”, where large amounts of mulch are hilled up around tree trunks, contributes to the spread of bacterial and fungal diseases.  Always aim to create a moderately deep “mulch doughnut”, rather than a mountainous mulch “volcano”.

Tree Planting and Fertilization

Fafard Premium Topsoil packTree planting is also best done in spring or fall, when weather conditions are less likely to stress young saplings.  However, if you must plant in summer’s heat, “water in” the tree by filling the planting hole part way with water before installation.  If the surrounding soil is poor, thin or compacted, fill in around the tree’s root ball with a mix of the removed soil and an equal amount of high-quality, fertile planting material, like Fafard® Premium Topsoil.  Once the tree is planted, remember to water well, especially in hot, dry weather.

It is best to fertilize trees in the spring, just before the first flush of growth.  This growth slows down in summer, so the season is not optimal for fertilization.

Sitting under a tall shade tree with friends, family or just a good book is one of the best ways to spend a summer afternoon.  Timely summer tree care is the best way to ensure that you will continue to enjoy that experience for many years.

Planting a new tree with a child
Plant new trees in spring or fall. Spring planted trees need extra care through summer.

About Russell Stafford


Hortiholic and plant evangelist, Russell Stafford, transplanted his first perennial at age 7 and thereby began a lifelong plant addiction. He is the founder and custodian of Odyssey Bulbs (and Odyssey Perennials), an online nursery specializing in cool and uncommon plants. Russell also works as a horticultural consultant, freelance writer (Horticulture and The American Gardener magazines), and garden editor. He formerly served as Curator and Head of Horticulture at Fernwood Botanic Garden in Niles, Michigan and as the Horticultural Program Coordinator at the Center for Plant Conservation, then located at the Arnold Arboretum in Jamaica Plain, Massachusetts. His academic degrees include a masters in forest science from Harvard University.

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