Moisture and Good Growing Conditions Leading to Mostly Minor Issues

Growing conditions and lots of rainfall has fruit trees developing bumper crops, silver maple and elm tree seedlings popping up in lawns and landscape beds, and brown or purple spots appearing on plant leaves.

If fruit trees have a heavy crop, consider fruit thinning. If not thinned, heavy crops can lead to alternate year bearing, reduced fruit size and flavor, and branch breakage.

Thinning is best accomplished by hand picking fruits after the June drop, beginning about late June. June drop is a natural thinning where trees drop a number of small fruit due to poor pollination or a heavy fruit crop the tree cannot support.

Where feasible, and if needed, thin fruits by starting where fruits are clustered. Remove all but one fruit per cluster. If not clustered, space fruits about five to seven inches apart; removing insect or disease damaged fruit first.

The same conditions that led to many tree fruits led to a heavy crop of maple and elm samaras; which are the fruits of these trees. The result is numerous maple and elm tree seedlings growing as weeds in lawns and landscape beds.  

Regular mowing will kill tree seedlings in lawns making hand-pulling or herbicide control unnecessary. If you have a newly seeded lawn, don’t wait too long to begin mowing. As soon as the new grass is close to three inches tall, begin to mow. This will control tree seedlings and encourage growth and maturation of the new grass.

 In landscape beds, tree seedlings are easy to hand-pull if you do not wait too long and allow them to establish. They will only germinate for a short time so hand-pull tree seedlings as you see them.  If you wait too long, and they develop a strong root, they will need to be dug with a spade or killed with careful spot treatment of glyphosate or Roundup.

Leaf spot diseases of trees, shrubs and other ornamentals are mostly fungal. For these diseases to occur, specific conditions are needed. A susceptible plant, the fungus is present, and moisture is on the leaf surface for a certain period of time along with conducive air temperatures.

We’ve had these conditions this year, especially rainfall, and a variety of diseases are showing up. Fortunately, most are only cosmetic and affect plant aesthetics more than causing long term harm to otherwise healthy plants. Fungicide control at this time is not recommended for most leaf diseases on ornamentals.

By: Kelly Feehan, Extension Educator