Our Bradford pear tree fell over last month (onto the overhead wires). We don't know why. We were advised to try a Callery pear variety, which would not have the same weak wood. Is this true?
Bradford pears are a variety of Callery pears. Callery pears are an aggressive Asian species, but Bradfords were supposed to be sterile. They are not. In fact, with interpollination between Bradfords and new Callery pear varieties, there are now millions of these alien trees spreading over the Eastern U.S. This displaces native trees necessary for our wildlife and a healthy environment. The bottom line is that no ornamental pears are recommended. All the Callery pears are also susceptible to fire blight, a bacterial disease that can weaken and kill trees.
Why are some of my spinach leaves yellowing? It's a fall crop in a full-sun, raised bed. I fertilized with blood meal and fertilizer, thinking it was caused by a lack of nitrogen, but the problem persists throughout the bed.
Many factors can cause the symptoms you describe. The most likely cause is a combination of low temperatures and a related nutritional deficiency. It is not a good idea to apply nitrogen fertilizer at this time because spinach can actually store too much nitrate under cool, low-light conditions, making it inedible. Remove the affected leaves.
Plant of the week
Chinese evergreen
Aglaonema modestum
For an easy beginner houseplant, we nominate Chinese evergreen. It provides waxy, undulating leaves that are 8 inches long on sturdy stalks about 1 to 2 feet high. Grown mainly for the foliage that can be solid green or variegated, it may flower in late summer or early fall with a pale jack-in-the-pulpit type of flower, followed by long-lasting bright red berries. Chinese evergreen takes moderate to low sunlight, never direct, as well as normal room temperature and humidity. For an extra shot of humidity, place the pot on pebbles in a tray of water. In wider pots, more plants may pop up. Feed monthly when actively growing.
— Ellen Nibali
