Extension Educationin Williamson County

I took the opportunity during the sunny weather last weekend to do some pruning on my trees.  Actually, I recruited my dad to help me do some pruning.  I pointed and he cut, and I certainly got the better end of the deal.

January is a great time to prune because many of our trees have lost their leaves, making it easy to see the limb structure.  Late winter is a good time to prune for the health of the tree because it is right before they put on new growth.  You do not want to prune late in the spring after the new growth comes out because a tree uses a lot of its stored energy to put on new growth.  Pruning off the new growth can stunt the tree.

When you prune, be sure to make clean, smooth cuts.  Do not leave stubs and avoid tearing the bark.  When cutting heavy branches, use a three-part cut.  Saw an undercut from the bottom of the branch about six to 12 inches out from the trunk and about one third of the way up through the branch.  Then make a second cut from the top, about three inches further from the trunk.  This undercut will stop the bark from peeling when you make the second cut.  The second cut removes a lot of weight from the branch so you can make a clean third cut.  Use the third cut to remove the stub back to the branch collar.

The branch collar on trees is an interesting intersection.  The branch collar is the swollen area of trunk tissue that forms around the base of a branch.  The collar is an area of tissue that contains a chemically protected zone.  In the natural process of decay on a dead branch, the decay advances downward until it meets this protected zone in the branch collar.  The dead branch falls away at the collar, leaving a very small zone of decayed wood in the collar that the tree can wall off.  What a neat natural protective process for the tree!

A good pruning cut is not flush with the trunk but is slightly angled to avoid the branch collar.  Leave the branch collar so the tree can quickly wall off the damage from the cut and heal over the wound.  You can tell a tree is covering over a wound when the rounded edge starts growing over the cut.

A lot of folks want to use pruning paint to help trees heal quickly.  Research shows that pruning paint can slow down the healing process.  We only recommend painting your cuts on oak trees to prevent the spread of oak wilt through the Nitidulid beetle.  When pruning oaks, paint the wounds within 15 minutes of making the cut.

Some pruning jobs require the help of professionals, for your safety and the safety of whatever might be underneath a large branch.  For big jobs, I recommend hiring a certified arborist who can help you determine what to prune and do it correctly.

For more information on lawn and garden topics, contact Kate Whitney, Horticulture Extension Agent, at 512-943-3300.

This week, I received a question from a concerned home gardener about a disease on red tip photinia.  Before I saw the pictures included in the email, I had a good hunch about the culprit.

Red tip photinias became popular in the 1960’s as a privacy screen.  This large shrub has beautiful spring color and can be found lining many fencerows in older homes.  Unfortunately, red tip photinia faces a devastating disease issue called entomosporium leafspot.

Entomosporium leafspot is a fungal disease that affects woody ornamentals in the rose family.  Indian hawthorne is another shrub impacted by entomosporium leafspot.  This fungus does the most damage when we have frequent fall and spring rainfall, temperatures are between 60 and 80 degrees, and the plant is actively growing.

The first symptoms are bright red spots on the new leaves that can join to form large maroon blotches in heavily diseased plants.   The fungus might just cause leaf drop in minor infections, but over time it can kill the whole plant.

If you have a light infection of entomosporium leafspot, you can help slow the spread by removing fallen leaves to reduce fungal spores.  Try not to allow the foliage to remain wet, so water in the morning and use drip irrigation if possible.

New growth increases the susceptibility of the plant to infections, so limit pruning and excessive fertilizer to prevent a lot of new growth.  Fungicides such as thiophanate-methyl and myclobutanil can be sued when conditions are favorable for the disease.  You have to time the application to cool, wet weather.  Fungicides are not effective during hot, dry weather.

Unfortunately, entomosporium leafspot is destructive for red tip photinia and Indian hawthorne.  If you have this fungus for long, you might consider removing the shrubs and replanting with other options.  The “Grow Green: Native and Adapted Landscape Plants” guide has some great recommendations for our area of Central Texas.  You can find it free online or at most local nurseries for purchase.

For more information about lawn and garden topics, contact County Extension Agent Kate Whitney at the AgriLife Extension Office at 512-943-3300.

During the winter months, there are a few plants that really get a chance to shine when our deciduous trees and shrubs shed their leaves.  I enjoy seeing the bright green leaves or pops of red from various hollies.

One of my very favorite small trees in the winter is the Possumhaw holly.  I love a plant with a good name, and this certainly has one.  The “haw” part of the name comes from the reddish fruit that looks similar to hawthorn fruits.  The “possum” part of the name comes from a certain furry critter that likes to snack on the fruit.

Possumhaw is native to a large area of Texas and can adapt to a wide range of soil conditions.  It can grow in shade to full sun, so it is a versatile plant for the landscape.  Possumhaw is really a large shrub or small, multi-trunked tree.  The height is typically eight to 12 feet, but it can reach up to 20 feet tall.  It grows six to 10 feet wide.

One of the things I love most about Possumhaw holly are the bright red or orange fruit that is a blaze of color in the fall and winter.  The small tree is deciduous, which means that the leaves fall off in the fall, but that only allows the fruit to show up even brighter!

Possumhaw is also dioecious, meaning that the male and female flowers are on separate trees.  To get good fruit set, a female plant needs a male plant nearby for good pollination.  The fruit sets on a female tree, and they are really beautiful when they are covered with bright berries.

Keep an eye out for the bright spot of color from a Possumhaw holly this winter.  For more information about lawn and garden topics, contact Kate Whitney, Williamson County AgriLife Extension Agent for Horticulture, at 512-943-3300.

One of my favorite parts about wintertime is the fresh citrus available.  Have you ever received a box of Texas grapefruit for a Christmas present? Those are a great treat!

The Lower Rio Grande Valley is known for citrus production.  Orchards were established along the coast as early as the 1880’s.  The Ruby Red grapefruit was developed in the late 1920’s and patented in 1934, leading to a rise in the Texas citrus industry.  At its height in the 1940’s, the Texas citrus industry had more than 100,000 acres planted throughout the Valley.

Severe freeze is the most limiting factor in citrus production, and Texas has had its share of hard freezes throughout the last half century.  A few major freezes in 1983 and 1989, along with economic factors and urbanization, led to a decline in citrus acreage.  Today, Texas has about 27,000 acres of citrus production grown in a three-county area in the Lower Rio Grande Valley.

Occasionally, I receive questions from folks who want to grow citrus in Williamson County.  You have to be a little bit brave and stubborn to grow citrus this far north, but it can be done!  We have some new varieties now that can handle the colder temperatures, and with the right care you can grow citrus in your backyard.

Satsumas are a type of mandarin orange that can handle cooler temperatures in our area.  You can also look for kumquat, calamondin, and Changsa tangerine.  Limes, Meyer Lemon, and citrons can also grow here, but will be severely damaged if temperatures drop to 23-28 degrees.

Try planting citrus in large pots that can be brought inside during cold weather.  Citrus plants that have survived a few seasons in Texas might be put in the ground if you can find a sunny location that is protected from northern winds.

For more information about growing citrus, visit the Fruit and Nut page on the Aggie Horticulture website: https://aggie-horticulture.tamu.edu/fruit-nut/ or contact Kate Whitney, Horticulture Extension Agent, at the Williamson County AgriLife Extension Office at 512-943-3300.

I am the daughter of a county extension agent, further proof that the apple does not fall far from the tree.  In the late 1980’s, my dad worked on a project called “Don’t Bag It!”  that encouraged homeowners to leave their grass clippings in the lawn, rather than bagging them.  The goal was to help reduce landfill waste and use grass clippings to return nutrients back into the soil.

When it came time for my first public speaking contest as a young 4-H member, my parents dressed me up in green tights and a trash bag and I got to speak about the benefits of “Don’t Bag It!”.  I won first place, and that lesson about not bagging yard waste has stuck with me.  Wearing a trash bag tends to imprint important lessons on impressionable young minds.  Thanks mom and dad!

Did you know that leaves are also a great source of nutrients for your lawn?  Leaves contain 50 to 80 percent of the nutrients a plant takes from the air and soil during the season.  This means that you have a free, organic source of fertilizer right in your backyard!  You do not have to worry about raking and bagging leaves anymore, saving your back and your pocketbook.

Leaves can be used in the home landscape in a few different ways.  A light layer of leaves on the ground can be mowed and left in the lawn.  This is simple and fast, and you will barely see the leaves in the lawn after you have mowed them.  The leaves will continue to breakdown and be a good source of fertilizer for your lawn.

You can also use leaves as a mulch in your landscape beds or vegetable garden.  Mulches reduce evaporation from the soil surface, inhibit weed growth, moderate soil temperatures, prevent erosion and compaction, and release valuable nutrients into the soil. One easy way to collect and shred the leaves is to use the bagging attachment on your mower. Then you can put the shredded leaves wherever you need them, such as around trees and shrubs, in flower beds, or in between rows of your vegetables for a good walkway.  Leaves that have been mowed or run through some type of shredder will stay in place better and decompose faster.

Leaves can also be used to improve your soil.  A six to eight-inch layer of leaves tilled into heavy clay soil will improve aeration and drainage.  Fall is a good time to work the leaves into the soil of your vegetable garden or annual planting beds because the leaves will decompose over winter and be ready for spring planting.

If you plan to do some yardwork this weekend, remember: Don’t Bag It!  For more information about lawn and garden topics, contact County Extension Agent, Kate Whitney, at the Williamson AgriLife Extension Office at 512-943-3300.