- Author: Ed Perry
We recently wrote the blog post “Wait! Don't Prune Apricot and Cherry Trees Just Yet,” to caution gardeners against pruning these trees in winter. Now we'd like to discuss when and how to prune avocado and citrus trees.
Avocados
Most avocado trees need little or no pruning. Whenever possible, allow them to develop naturally. Avocado leaves produce and store food for the tree. If this food supply is reduced by pruning, fruit production will also be reduced. Usually, removing dead or weak branches is the only pruning you need to do. Avoid pruning in late summer and early fall, as this stimulates new shoot growth that is susceptible to frost injury. In general, remove as few green branches and leaves as possible.
If you need to remove lower branches, prune them out completely, or cut them back to an upright growing shoot. Prune only after your tree has developed enough upper foliage to prevent sunburn damage on the lower limbs or trunk.
Sometimes a young tree grows tall without branching, grows sideways, or grows a top that is unbalanced. Correct these conditions by cutting the unruly limb or trunk back to a strong lower branch, or by staking the tree. Keep in mind that avocado trees grow naturally in an irregular way and will develop a better structure if they are not pruned at all. If you want to control the height, it's best to do so while the tree is young.
To prevent tall, upright growth, pinch back the terminal bud of the upright shoots on the young tree. Repeat this after each growth flush during the first few years. Your tree will spread out to the sides and develop a more compact form. If you reduce the size of an older tree by heading back large branches in the top of the tree, be sure to thin out the new growth which follows. Otherwise, the tree will soon grow back to its original height.
Citrus
If necessary, light pruning can be done in citrus trees any time of year. However, the best time to prune citrus is in early spring, after danger of frost has passed and before the start of spring growth.
Nearly the same rules for avocado trees apply to pruning citrus trees. The foliage of a citrus tree is an important food (carbohydrate) storage area. Pruning removes foliage and stored foods and causes the tree to produce a flush of vegetative growth instead of fruit. For the most part, prune out only dead or broken limbs.
Citrus trees normally produce vigorous shoots from the base of the tree called suckers, which you should remove as they grow. Vigorous shoots that grow from branches are called watersprouts. Remove watersprouts if they are not well placed but leave them whenever possible. Young trees need no pruning for the first two or three years after planting, except to remove suckers. As the tree grows older, prune lightly only to remove branches which are too closely spaced or entangled. Do not remove low-hanging branches, as they bear fruit within easy reach and shade the trunk and soil. The ideal citrus tree has a skirt of foliage that extends almost to the ground. Left alone, citrus trees normally develop an even, round-headed shape as they mature.
Lemons usually need a bit more pruning than other types of citrus. Cut back some of the more vigorous shoots on young trees. Lightly thin the branches of mature lemon trees each year to improve the size and quality of the fruit.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County.
- Author: Anne E Schellman
Weeds may grow more slowly this time of year, but they can still be a problem. Most of the weeds found in gardens and landscapes now are winter annuals. These weeds germinate in late summer or fall and grow during cool weather.
Annual weeds flower and set seed in spring and die in summer. Some of these weeds can produce hundreds to thousands of seeds per plant! As you may imagine, these weeds can quickly become difficult to control once established. The best time to control weeds is when they are small, before they bloom and set seed.
Manage annual winter weeds by hand pulling or hoeing, making sure you remove the entire root. Once you've cleared an area, apply 3-5 inches of mulch. Monitor your landscape weekly, pulling any weeds that emerge. Be aware that organic mulches break down and must be replaced every few years.
Young weeds in open areas can be killed using a small flaming tool. You can find these at local hardware stores or nurseries. In difficult cases where you have trouble getting control, you may want to use an herbicide. Be sure to identify your weeds before choosing a product. Read the label before application and follow directions carefully.
If you aren't sure what weeds you have in your garden, you can bring in samples to the Stanislaus UCCE Master Gardeners. Reach us at (209) 525-6800 or visit our office between 8:00 a.m. and 4:30 p.m. Monday through Friday, at the Agricultural Center on 3800 Cornucopia Way, Ste A in Modesto, 95358. You can also email photos to ucmgstanislaus@ucanr.edu.
For more details on weed control, consult the following UC IPM Pest Notes: Weed Management in Landscapes and Weed Management in Lawns. 
- Author: Anne E Schellman
Pests need food, water, and shelter to live. Unfortunately, some of us unknowingly attract and even invite pests to live in and around our homes!
Insect and animal pests can pass through small spaces. For example, mice can get through a hole the width of a pencil, and cockroaches can flatten themselves and squeeze through cracks. Here are some circumstances that attract pests, allow them access, and provide them with food, water, and shelter:
Pest Attractors and Supporters
- Pet food and water bowls (indoors and outside)
- Bird feeders
- Leaking water spigots
- Open food packages in your kitchen
- Hedges and shrubs near doors or windows
Entry Points
- Holes in windows and screen doors
- Cracks in the foundation of your house
- Holes in the roof or attic
- Crevices around pipes indoors (bathrooms, laundry area, kitchens) and outside
Use IPM to Manage Pests
Use integrated pest management or IPM to help you pest proof your home. First, walk in and around your home to inspect for the above pest attractors, supporters, and entry points. Once you find a pest, for help with identification contact the UCCE Master Gardeners of Stanislaus County at (209) 525-6800.
If you can't personally inspect your home or don't have time, you can call a pest control company and ask them to do it for you. This is helpful for hard to access places like basements and attics.
For Quick Tips on common pests and their management and prevention from the UC IPM website, click below.
Other Helpful Links
What is IPM?
UC IPM Website
Pest Notes Library
Stay in touch! Follow us on Facebook or Twitter @UCMGStanislaus
- Author: Ed Perry
Did you know that fallen leaves can become a valuable garden resource? You can turn these leaves into compost. Although low in essential plant nutrients like nitrogen, the leaves still contain small amounts of all the nutrients plants need and are a valuable source of soil-improving organic matter.
Get started by chopping the leaves into smaller pieces before adding them to the pile. You can use a chipper or a shredder if you have one. Otherwise, run over them with a lawn mower and then mix them into your compost pile. If you have a lot of leaves, you can store them after shredding in garbage bags or containers, then occasionally layer them into your compost pile over the winter to add air to the pile.
Sometimes certain green materials, like grass clippings, become matted in the compost pile. When this happens oxygen is excluded, and the composting process may stop. Adding leaves helps keep the grass clippings fluffed up and aerated.
If you're new to composting, keep in mind that the decomposition process works best if you mix equal volumes of carbon-rich, naturally dry plant material (dead leaves, dried grass, straw, and woody prunings) with nitrogen-rich green plant material (grass clippings, wilted flowers, green prunings, weeds and fruit and vegetable waste). This mixture allows a “carbon to nitrogen” ratio of 30 to 1, which is ideal for efficient compost production. You can produce compost slowly or quickly. Here are two methods:
The Slow Method
Build a pile of organic materials and let it stand for a year, when the compost will finally be ready for use. The advantage of this method is that it takes relatively little effort. However, some nutrients may be leached due to exposure to rainfall, and low composting temperatures may not kill some weed seeds and disease-producing organisms. For more information on this method, download the leaflet Composting is Good for Your Garden and the Environment.
Rapid Composting Method
This process produces compost in as little as 2 to 3 weeks but requires more effort. It allows you to produce large amounts of compost quickly. For more details about this method, you can download the leaflet Compost in a Hurry.
Many local nurseries and the Modesto Junior College offer hands-on composting classes. In the future, our UCCE Master Gardeners plan to offer composting classes. Keep in touch with us by signing up for our blog and following us on Facebook and Twitter @UCMGStanislaus to hear about upcoming classes and workshops.
Ed Perry is the emeritus Environmental Horticultural Advisor for University of California Cooperative Extension (UCCE) in Stanislaus County.
The University of California Cooperative Extension (UCCE) Master Gardeners of Stanislaus County are holding a free Spring Gardening Class on Thursday, February 7, 2019 from 6:00-7:30 p.m. at the Agriculture Center on 3800 Cornucopia Way in Modesto at Harvest Hall, Rooms D&E.
Come learn which vegetables to plant and when to start seeds indoors for spring planting. Examples of vegetables we will talk about include:
- Beets
- Broccoli
- Cabbage
- Carrots
- Peppers
- Tomatoes
And many more! This class is free, but please visit http://ucanr.edu/spring2019 or call Anne Schellman at (209) 525-6862 to sign up. Space is limited, so please reserve your seat today.
This family-friendly class is open to everyone. Participants will receive free seeds (while supplies last). There is plenty of parking around Harvest Hall, but please come early if you've never been to our site. There will be signs to direct you to the classroom.
If you aren't already, please follow us on Facebook or Twitter @UCCEMGStanislaus.
