The Mighty Oak

Although oaks are relatively easy to care for, a few tips will help keep them happy and healthy.

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Filed under: Trees, Plants

America's national tree grows in almost every state in the union. Although oaks are relatively easy to care for, a few tips will help keep them happy and healthy.

Oaks are so long-lived and have such appeal in the landscape that planting one becomes a good investment--one that will outlive the house itself if a few special needs are met.

"Oaks have special needs," says arborist Joe Benassini. "They're adapted to long, wet winters and dry summers. When we landscape and build around them, we need to be very careful how we do that."

One of the most common mistakes that homeowners make is planting a lawn too near an oak and then watering that lawn regularly. Eastern oaks are moderately tolerant of these waterings, but oaks in the West are not. There, a good rule of thumb is don't soak the oak.

"My advice to anyone who is thinking about planting a large tree such as an oak would be to plan for size, plan for your tree, plan to landscape in accordance to your tree's needs, " says Benassini. Also, keep plenty of distance between the tree and your house. Oaks are slow growing, so in addition to gaining some impressive height, they can pack on the girth as well.

Some other basic rules:

Maintain the natural grade around the tree--a critical element in preserving the tree's root system.

Know the tree's water, light and nutrient requirements. Oaks need full sun, plenty of room to grow and can adapt to most soils. Mulching the young tree is a good idea in almost all cases. A natural mulch feeds the soil and allows the soil to feed the tree.

Figure A

Think compatibility when adding nearby landscape plants. A tree like the eastern dogwood would probably not be a good companion because its water requirements are incompatible with those of the oak.

Figure B

Check on your tree's health twice a year--in summer to check the foliage, and in winter for structure. Examine the tree at the root crown where the trunk meets the soil; look for mushrooms, unusual growths, bulges, cracks and flaking bark.

Figure C

If you find a sulfur conk, be sure to call an extension office. A conk is the fruiting body of a wood-decay fungus, a sure bet that there's significant decay inside the tree.

Figure D

From the root crown, move up the trunk and inspect the trunk, looking for cracks or unusual formations. Sounding the trunk may help detect internal decay, as well. Using a rubber mallet, Benassini knocks on the trunk and listens for hollow sounds, which may indicate internal problems. A visual assessment up the trunk can identify cracks, dead branches, and in the summertime, a sparse canopy. If you see a problem, consider consulting with an arborist or cooperative extension agent as your first line of defense.

Don't over-prune. "Pruning should only be done to manage the growth and safety of the tree," says Benassini. "So pruning should be kept to a minimum."

Figure E

Planting an acorn is simple. First, lay the acorn on its side and cover it with an inch or two of soil. Next, mulch with the leaves that have already fallen, and come spring, you should see some growth.

Growing, preserving and nurturing the impressive oak tree has another benefit. Oaks make us feel good; studies have shown that stately oaks contribute to positive emotional effects on the human psyche.