In this dry, hot summer it’s strange to think of over irrigation as a concern but, in fact, the dry season often causes a rise in the number of over irrigated trees due to overzealous watering.
Water is, obviously, essential to a plant’s health. Plants need consistent application of water to stay alive and healthy. However, it is surprisingly easy to over irrigate a tree. When a tree becomes over irrigated, or waterlogged, the roots can no longer properly absorb oxygen. Eventually these roots will wither and die from a lack of oxygen. This lack of oxygen can lead to decay of vital nutrient transport tissue. Trees that have been over irrigated need help, and fast.
Symptoms include yellowing leaves, scorched leaves, blisters that appear water soaked on the stems and leaves, and a general lack of vigor. To do some serious investigating, dig 8-10 inches into the tree’s root zone, in the area between the trunk and the edge of the tree’s canopy. If the soil here is moist or there is a sour smell coming from the roots, your tree is most likely waterlogged. Also keep an eye out for fungal vegetation around the tree’s roots.
If your plant appears to be waterlogged, STOP watering immediately. You now need to find out the cause of the overwatering issue. Common causes include heavy and poorly drained soil, poor tree placement or incorrect methods of watering. It can always be a combination of factors as well. Certain tree species can tolerate or even require a damper soil (river willow, birch) . You can always ask your local nursery, or even contact us for recommendations.
If you have a drip-watering based system, consider changing your method. Drip irrigation can be a cause of overwatering, especially for trees native to the area. Instead, try watering your tree along the edge of the tree’s canopy. Applicate to a depth of 18 to 36 inches.
Stop all fertilizer application if your tree is overwatered. Do not resume until the tree recovers. Too much fertilizer can scorch the tree roots, making them unable to absorb the moisture in the soil. Try using instead. These natural soil amendments supply beneficial microbes for the soil, and provide nutrients that strengthen the soil as a whole. Along with using natural soil amendments, implement a composting program as well. Top dress around the root zone with a 2-3 inch layer of organic compost.
- If it is a young tree, you can always implement the last resort method of transplanting the tree to a dryer location.
- Measure if your sprinklers are overwatering by placing a can in the watering zone. It should only fill up to an inch of water otherwise it is probably overwatering.
- The dryness of the soil surface is not necessarily indicative of the root soil’s moisture levels. Don’t overwater based on a dry surface soil, always check the root zone by digging or using a soil probe.