If you have a peach or nectarine tree you may have a tree with leaves that look like mine. I was hoping this year would be a “good” year and I wouldn't see this on my trees, especially since I didn't apply any dormant sprays this year, but no such luck.

Peach leaf curl first appears in spring as reddish areas on developing leaves. These areas become thickened and puckered, causing leaves to curl and severely distort. The thickened areas turn yellowish and then grayish white, as velvety spores are produced on the surface by the leaf curl fungus. Later affected leaves turn yellow or brown and can remain on the tree or may fall off; they are replaced by a second set of leaves that develop more normally unless wet weather continues. The loss of leaves and the production of a second set result in decreased tree growth and fruit production. Defoliation in spring may expose branches to sunburn injury. Periods of cool, wet weather, when leaves are first opening on the tree, favor the disease.

To prevent peach leaf curl, use resistant peach and nectarine varieties where possible. (See the Resistant Varieties section by clicking on the link below.) For nonresistant varieties, treat trees with a fungicide every year after leaves have fallen. In cooler northern locations leaf fall usually is in late November. Generally a single early treatment when the tree is dormant is effective, although in areas of high rainfall or during a particularly wet winter, it might be advisable to apply a second spray late in the dormant season, preferably as flower buds begin to swell but before green leaf tips are first visible.

For more information on Peach Leaf Curl, click here.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.

Grass clippings make up a surprisingly large portion of California's solid waste stream during the growing season. With few exceptions, it is actually best to leave the clippings on the lawn after mowing. This practice, termed “grasscycling,” is growing in popularity as California communities try to reduce the amount of waste going to landfills.

Grasscycling saves time and money, and helps the environment. Mowing time is reduced since bagging and disposal of clippings is eliminated. Grass clippings add valuable nutrients and organic matter to the soil and produce healthy, green lawns. About 20% of the fertilizer requirements of most grasses can be attained just by leaving the clippings on the lawn.  Grasscycling reduces turf grass fertilizer and water requirements, which minimize chemical runoff entering storm drains and polluting creeks, rivers, and lakes.

Grasscycling reduces the amount of yard trimmings disposed in landfills which historically have comprised half of the yard trimmings deposited in California landfills. Research has shown that lawns generate approximately 300-400 pounds of grass clippings per 1,000 square feet annually which equates to as much as eight tons per acre each year.

Grasscycling can be practiced on any healthy lawn as long as the turf is properly managed. Unfortunately, many people treat a lawn as if it were a crop: overwatering and overfertilizing it to encourage maximum growth, and then “harvesting the crop” by bagging the grass clippings and transporting them to a landfill. Successful grasscycling requires proper mowing. With frequent mowing, you will have short clippings that will not cover the grass surface if left on the lawn and will quickly decompose.

There are times, however, when grasscycling is not appropriate. Prolonged wet weather, mower breakdowns, or other circumstances that reduce mowing frequency and thus lead to an excessive volume of clippings probably dictate that the grass clippings should be bagged. But do not throw those clippings away! Grass clippings make an excellent addition to a backyard compost pile. Clippings can also be used as mulch to provide weed control and prevent moisture loss in flower beds and around trees and shrubs. In some situations, however, you should not mulch with clippings: if the clippings are of an invasive species such as bermudagrass or if herbicides were recently applied to the lawn, the clippings can be harmful.

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.

Information was taken from the UC Guide to Healthy Lawns

The buzz of lawnmowers has become a familiar sound at the start of this spring. If your lawn is anything like mine, it's growing like crazy with this warm then wet weather we have had.

You might not think there is much to mowing your lawn but proper mowing, combined with other lawn maintenance practices, is critical for attractive, well-groomed lawns. One of the biggest mistakes people make is mowing too short. The following was taken from the UC Guide to Healthy Lawns.

Optimum cutting height is determined by the growth habit of a particular grass and its leaf texture (i.e., the length and width of leaves). A grass's survival depends on its producing adequate leaf surface for food production through photosynthesis. Mowing too low removes too much of the grass's food producing area. As the grass literally starves, the lawn thins and looks poor. Conversely, mowing too high can hurt the appearance or usefulness of the turfed area.

No single mowing height is best for all turfgrasses; mowers must be set differently for each grass. The table below shows the ranges for optimum mowing heights for California lawns. Within its optimum mowing height range, each grass species will be healthier and have a deeper root system the higher the grass is mowed. Also, within its recommended mowing range, a grass that is cut higher is more tolerant of drought, heat, traffic, shade, disease, and pests than one that is cut lower.

As a general guide, follow the one-third rule: mow often enough so that no more than one-third of the length of the grass blades is removed at any one time. For example, if you maintain a turf-type tall fescue lawn at 2 inches, mow it when the grass height reaches 3 inches. This may mean mowing tall fescue once a week during the spring and every two weeks during the summer. The table also gives the height at which you need to mow your lawn in order to best maintain your desired lawn height. A lower-mowed lawn will require more frequent mowing than that same lawn would if mowed higher.

ADDITIONAL MOWING TIPS

• Do not mow wet grass: it sticks to mower blades and clogs the mower.
• Change the direction of mowing periodically to prevent a “washboard” effect.
• Sharpen lawnmower blades regularly. Dull mowers leave a ragged appearance from crushed or uncut grass blades, and damaged grass may be more susceptible to disease.
• Do not drastically or suddenly change the cutting height. If the grass has become too tall, re-establish the recommended height by mowing more frequently for a while and gradually lowering the mowing height of successive cuttings, following the one-third rule.
• Since mowing stresses the grass, do not mow a lawn under drought or other climatic stress conditions. Grass that is suffering from lack of water should be watered and allowed to dry before being mowed.
• Mow a shady lawn slightly higher and less frequently than is normally recommended for that grass species. Shade reduces photosynthesis, and slightly higher mowing heights allow more leaf surface that compensates for the lower light levels

Stay tuned for more posts related to healthy lawns. If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.

Spring is when we run to the nursery, anxious to get started after oggling garden magazines all winter. Those six-pack annuals are so tempting and, fortunately, innocuous, but there are a few truly dangerous specimens lurking out there, waiting to take over your garden and then some!

Invasive species take advantage of conditions where their natural controls, such as pests and disease, are often absent. This allows them to grow like crazy, displacing native plants and the animals that depend on them, reducing the biodiversity essential for a healthy ecosystem.

Some invasives can be found in nurseries and are best avoided:
1. English Ivy is a familiar sight in urban and suburban gardens. This creeping vine forms “ivy deserts” where it outcomptes other plants for light and water. The thick, waxy foliage makes herbicides largely ineffective. Don't buy it; if you have it, consider having it removed.

2. Periwinkle spreads by rooting wherever it's stems touch the soil. It is especially dangerous in riparian areas where even a small piece can wash downstream and become established. Remove by pulling out all root nodes and stolons. Do not remove by mowing; the chopped-up pieces are likely to re-root.

3. Broom (Scotch, Bridal, French, Portuguese, Spanish) produces copious seed and biomass which is a fire hazard in some areas. The foliage is nutritionaly lacking and has little livestock value. Some cultivars are said to be “sterile”, but these claims have not been verified.

The California Invasive Plant Council has a list of top 15 invasive plants that are a concern in the Central Valley. Don't worry if some of your favorite plants are on the list; Cal IPC has substitutes as well!

If you have a gardening related question you can contact the UC Master Gardeners at 209-953-6112. More information can be found on our website.