Garden docs: How to save maple trees from sunburn

Henry R. asks: My Owari Satsuma failed to produce the abundant amount of fruit this year. I was told that many fruit trees bear heavily one year and sparsely the following year. I thought it was probably the strange weather patterns that have taken place. Any thoughts?

No. They are self-fruitful. Meaning they produce fruit through self-pollination. Each flower has both male and female parts.

You may be right about the weather patterns affecting your production. Other gardeners have inquired about the same problem and the fruit not being as sweet as in the previous year. Hopefully, you will have an abundance of blooms producing plenty of mandarins in November through next few months.

Fruit crops that are heavy one year and light the following year are referred to as alternate bearing. Alternate bearing is more common in deciduous fruit trees such as apples and apricots. The spring flowering buds form during the previous year’s spring and summer. When a crop is heavy the previous year, it may use most of the carbohydrates it produces through photosynthesis to produce that year’s fruit. The following year the crop is meager. There is a way to correct the problem by thinning the fruit early after petal fall and during fruit formation.

Julie R. writes: I purchased three new maple trees for my front landscape and was advised to take measures to prevent sunburn on their tender bark. Also, I was advised to plant high because of heavy clay soil. The trees are in 15-gallon containers. How should I prevent sunburn?

You received excellent advice. Prepare the site by mounding the soil several inches and dig the hole wider than deeper to prevent the tree from sinking and creating a standing water situation.

New trees require more frequent irrigation but not so much that its clay soil is soggy. Check the soil a couple of times a week, especially during the hot and windy summer weather. Mulching heavily around their trunks will keep the soil cool and retain moisture while they are getting established.

Extreme exposure to high temperatures can cause sunburn leading to dehydration and death. This is especially prevalent when trees are planted close to sidewalks and receive an overdose of reflected sun and heat. Also, trees planted adjacent to street blacktop receive additional harmful heat and reflected sun rays. Sunburn will crack the bark and open up the surface cambium to insect invasion.

One of the easiest ways to prevent sunburn is painting a mixture of 50% white latex paint with 50% water to the tree trunk. This is especially important while the canopy is developing. Also, avoid pruning off the small branches on the lower trunk. They are protecting the tree from sunburn and can be pruned off later on as the canopy enlarges.

If the tree requires some support, create some shade and sunburn protection by placing stakes on the south/southwest side of the trunk. Remove the small stake that was tied tightly on to the tree at the nursery. It seems people feel it is important to leave it in place while adding additional tree stakes. Allow the large tree stakes to do their job while the tree is getting established.

Joseph writes: How important is it to remove the spent blossoms from azaleas and rhododendrons? How do I disbud roses to create larger blooms?

Actually it is a smart gardening task because an estimated 70% of rhododendron’s energy goes into the formation of seed. You will want all of that energy to go into the next season’s flower production.

Try the simple trick of taking a whisk broom to gently brush off the spent azalea flowers. Use small pruning shears to carefully remove the rhododendrons’ spent blooms above the two new leaflets.

Remove small side buds on the rose to encourage a large center bloom. On floribundas rose clusters, remove the middle bud that blooms first.

Dana Lozano and Gwen Kilchherr are garden consultants. Send your gardening questions to The Garden Doctors, at pdgardendoctor@gmail.com. The Garden Doctors can answer questions only through their column, which appears twice a month in the newspaper and online at pressdemocrat.com.