Winter Newsletter
Pruning
Whenever a plant is pruned an open wound is created.
Although pruning of woody plants can be done any time of year to remove weak, injured, dead, dying, crossing branches or water sprouts, the winter dormancy period is the best time to prune most vines, shrubs and trees especially deciduous trees. However, for spring blooming trees and shrubs prune as soon as possible after bloom is finished, especially Camellia and Rhododendron family. Avoid pruning when decay is apparent to reduce the spread of fungal spores, usually in warm moist weather.
Pruning at the right time reduces the risk of disease or pest infestation and wounds heal faster. Pruning during dormancy means less sap is flowing and a wound will not bleed as happens in certain plants. The sap can attract pests.
A gardener will need hand shears (up to ¾” diameter), loper (up to 1” diameter) and pruning saw (greater than 1” diameter) available at most garden centers. PHOTO: (see above) Gonicc 8″ Professional Sharp Bypass Pruning Shears, available from Amazon.
Watering & Irrigation Systems
If it is raining, turn off the irrigation system. For established in ground shrubs and perennials, if the soil is saturated, wait about a month once the rain has stopped, before turning it on. Then program it for only once a week with enough duration for deep watering to reach a bit beyond the root zone. If the weather turns warm, then it’s best to watch the plants for color loss and signs of wilting. Far too often, irrigation systems are unnecessarily and detrimentally programmed with too much frequency with not enough time, resulting in shallow root systems. With trees, there can be a loss in stability and hardscape upheaval. Watering in this fashion cannot improve plant development and water is actually wasted because it is not being utilized well and is not optimally serving its purpose.
When it’s time to turn on the irrigation system, if water run-off occurs and not enough has been applied for the root zone (dig to get a sense about this as a starting guide to understanding), then program the automatic controller to just before run-off, but with multiple cycles during that same day. Wait a few hours between each cycle to allow the water to be better absorbed and by gravity to move downward to the root zone. This will be a more efficient and effective way to help plants and to reduce waste.
Do not plant or work the soil if it is saturated; it will compact. Wait until it is friable and has more air for best structure for plant roots.
Feeding
Feed Citrus trees at least quarterly with a nitrogen, phosphorous, potassium fertilizer with an N-P-K ratio of 2-1-1. If leaves continue to yellow, it’s best to have a soil lab analyze a sample for possible deficiency of nutrients. You can use a complete fertilizer with trace minerals, but San Francisco bay area soils are often high in zinc and this can cause imbalance, toxicity, poor performance and reduce longevity. Controlled release fertilizers are good for young trees up to 3 years old.
Weeding
Weeds will continue to sprout and grow when moisture reaches the soil.
A few mechanical controls include:
- Hand weed to remove roots not just foliage. An excellent tool for this is the hori hori.
- Mow often to starve weeds and do not let weeds go to seed.
- Rototill large areas, or turn weeds into the soil with a shovel or spading fork for smaller more manageable spaces. Do not work the soil when it is wet, moist is best. Not as effective as other methods because roots will remain and some will resprout, but this has the advantage of incorporating vegetative matter into the soil to decompose and provide humus and nutrients.
- Smother weeds with cardboard or newspaper when sprouted or after mowing. To get existing weed seeds to sprout, water well, then wait a couple of weeks for them to germinate, then cover. If getting all the weeds out is important, the process may need to be repeated.
Once existing weeds are under control, an excellent organic control is to maintain a continual 2-3” layer of organic mulch to help suppress weeds. More about the benefits of mulch in the next newsletter.