Garden sage: Stinky pear trees; avoiding 'mouse mayhem'

A: You are correct. The tree in question is a callery pear (Pyrus calleryana). These are ornamental pear trees bred to produce flowers and not edible fruit. They became very popular in the last quarter of the 20th century and can be found in many cities and towns as a street tree. The variety most seen is ‘Bradford’ although there are at least a couple dozen others. The flowers have an unfortunate odor as you noticed and are best observed at a distance. Another unfortunate feature of Bradford pears is their branch structure. The tendency for branches to grow from the trunk at sharp angles predisposes these trees to break in high winds. The one thing this tree has going for it is resistance to fireblight, a disease that affects other pear trees. The newer varieties have been bred for better features but fireblight continues to be a concern.

Q: How can I keep the mice out of my compost? One of the most terrible days of my life was last fall when I used a sharp-bladed shovel to dig out last year’s compost pile. Suddenly and unexpectedly I heard the shrill and amazingly loud screaming of mice. As I quickly removed my shovel I saw with horror that it had sliced a mouse nest in half, decapitating, killing, and wounding three of the blind, hairless baby mice. The two unharmed baby mice I put back in the compost where they were soon rescued by the parents. But I never want to have that experience again.

After the catastrophe, I got rid of my old compost bin that used to sit on the ground and replaced it with a plastic bin raised up 2 feet from the ground on metal legs. I used metal mesh to seal the base of the bin in case mice could actually climb up the slippery metal legs, and this I thought would keep the mice away from my delicious kitchen scraps. Now, two months later I again see small gray mice inside the compost bin. It is winter and they want to be warm and not hungry, but I dread what will happen in the early summer when I want to use that compost in my garden. Any ideas of how to avoid another mouse tragedy?

A: It is difficult to keep rodents out of anything. If you weren’t so concerned about the mice, I would recommend snap traps baited with peanut butter near the base of your compost bin. Since you are concerned, the best bet is excluding them from the compost bin. Exclusion could work with your current compost bin if you can use mesh with small enough holes that they cannot squeeze through. Hardware cloth with quarter-inch holes should be enough to keep out adult mice. Using a bin with a lid can also aid in exclusion. Another idea is to make this compost habitat less appealing by turning your compost once a week. Turning compost with a pitchfork can result in the same deathly experience if not done frequently enough. There are also the sort of bins that can be turned with a crank if that is more your speed. If composted material is decomposing ideally, it reaches a fairly high temperature in the middle and no mouse is going to set up housekeeping in that heat. In the end, you might have to just be more careful digging around the top of your compost pile to avoid more mouse mayhem.

Q: I have a question about trimming our two dwarf grapefruit trees. We just removed all the fruit from them. We would like to trim up the bottoms (they both touch the ground, and when the fruit comes on and grows larger, they are very weighed down). There are some dead limbs in the middle also. Can we trim the citrus trees now before they start to bloom for the next batch of fruit?

A: Yes, you can prune your trees now. Dead limbs and sprouts (aka watersprouts or suckers) can be removed any time. Between February and April is best for pruning live branches. This allows the tree to leaf out and protect any limbs that may be exposed to sun. What is commonly called skirting or limbing up from the bottom should be done carefully to avoid taking off too much. The natural shape of these trees helps protect the bark from too much sun and resulting scalding damage that could occur. Removal of the low-hanging branches should only be to improve access to the soil surface, the irrigation system, or to the interior of the tree. Citrus wood is naturally strong and is not as likely to break under the stress of a large fruit load. Furthermore, citrus trees can produce fruit in all but the most shaded part of the tree, and need not be regularly pruned to allow light into the interior of the canopy. Even when the crop load is heavy, individual fruit size is large, so pruning to reduce the crop load and improve fruit size is not necessary except occasionally with tangerines. Finally, citrus fruit quality is typically just as good or better from a minimally pruned tree as compared with one that is heavily pruned. Lower canopy fruit often is of the best quality because it is not often affected by sunburn, scarring by windblown soil particles and by the movement of adjacent branches and twigs, or by bird predation.

Q: I would like to know when and how and what type of fertilizer I should use for plum, apricot, peach and fig trees. My trees are 2 to 3 years old.

A: Once established, fruit trees need to be fertilized each spring to ensure that new healthy growth occurs and fruit will be large and tasty. For trees of 2 to 3 years of age, you can use 3/4 of a pound of a complete fertilizer that contains nitrogen, phosphorus and potassium. Spread the fertilizer evenly under the tree near the edge of the crown of the tree, also known as the drip line where rain falls and your drip irrigation should be installed. Timing your irrigation to coincide with fertilization will help the fertilizer reach the roots and protect the roots.