I have a well-established, twenty-year-old Wisteria vine climbing up the front of my porch. Unfortunately, by the fall, it's always out of control. Can I trim it back during the year without jeopardizing next spring's blooms? Also, how might I help increase the flowers as it doesn't tend to put out an abundance of blossoms?
Gardeners are reluctant to prune plants, especially vines, fruit trees, and roses, once the primary pruning season is completed.
When quizzed about why not, the most common answer is "It may die," or it will stop blooming. Plants never die from such pruning practices; however, flowering issues may develop related to off-season pruning. These issues are easily overcome with some basic plant knowledge about the plant(s) in question.
Wisteria is traditionally pruned in the spring after flowering. This is the time to establish the basic shape and perimeters of the plant. Then, during the growing season, it's okay to prune off any of the shoots that are growing in the wrong direction.
Wisteria blooms on the second year and older wood or shoots. With my Wisteria, I'm forever cutting the shoots out of the eves and a nearby orange tree.
I'm not worried about the flowers, as there will be plenty of growth for the Wisteria to bloom next spring. You can improve the flowering by lowering the soil pH. The pH scale is from one to fourteen, with seven being neutral.
Any reading above eight is said to be alkaline, while soils below 7.0 are said to be acidic—Wisteria-like a soil pH around six to six point five. You can purchase a simple pH kit at your favorite garden center.
Since our soils are somewhat alkaline, I'd apply Soil Sulphur, Greenall pH Adjuster, or a similar acidifier to lower the pH. The nursery professional at your favorite garden center has the right solution. The beginning of the rainy season is an excellent time to apply these products.
Also,Soil Acidifiers benefit Azaleas, Camellias, Rhododendrons, Gardenias, other shade-loving plants, and Blueberries.
I'm curious as to why people don't plant Pistachio trees and harvest the nuts.
Pistachio trees will grow and produce in the warmer inland areas of the Bay Area. However, they're not recommended for today's smaller yards.
They're slow-growing, medium size trees, reaching a height of thirty feet. You'll need a minimum of two trees, one male and one female, for a yield, as there are no self-fertile varieties available. Commercially, one male is planted for every eleven females.
Pistachio trees prefer growing in soils that drain and suffer from constant summer moisture; hence, you can't utilize the space under the canopy with other plants. This makes them impractical for most Bay Area yards.