by Shirley D. Smith, Somervell County Master Gardener

One of the main reasons we bought our property in Somervell County was because of a stand of live oaks.  We built our house close to these trees and they have given us a lot of pleasure as we sit under them on a summer day and enjoy their shade or just admire their beauty.  Grandkids have spent hours climbing their twisted branches.  However, after becoming a Texas Master Gardener and attending some classes on how to keep trees healthy, I learned of a destructive disease that can take down every one of these huge, majestic trees!  In layman’s terms, it’s called Oak wilt.  The scientific name for the fungus is Ceratocystis fagacearum and it is one of the most destructive diseases affecting live oaks and red oaks in Central Texas.

Because live oaks tend to grow from root sprouts and can form root grafts very readily, all or most of the live oaks within a given area share a common root system.  Most of the tree mortality results from tree-to-tree spread of the pathogen by these interconnected or grafted root systems.

Oak wilt has been found in over 76 counties and in almost every city in Central Texas, as well as Abilene, Midland, Lubbock, Dallas, Fort Worth, College Station, Houston and San Antonio.  In can be a problem wherever live oaks tend to be the predominate tree.  It does not matter whether they are transplanted or naturally grown and an individual tree’s age, size or previous health status does not make it more or less likely to die from oak wilt.

Oak wilt spreads to other oak trees in two ways:  long distances with the aid of certain beetles or locally through common or grafted roots.  Sap-feeding (nitidulid) beetles are believed to be responsible for much of the long distance spread of oak wilt.  During the spring, the oak wilt fungus forms special spore-producing structures called fungal mats on red oaks. Nitidulid beetles are small (about 1/8-inch long) and are attracted to oak wilt fungal mats because the mats have a sweet, “fruity” smell. Mats form underneath the bark of diseased red oaks and are not known to occur on live oak trees. The fungal mats apply pressure under the bark causing a tiny crack to form.

These mats can be found on the trunk and major branches of red oaks. When a nitidulid beetle feeds on an oak wilt fungal mat, spores of the oak wilt fungus will cling to the body of the beetle. Nitidulid beetles also feed on tree sap associated with fresh wounds. If a beetle contaminated with oak wilt spores lands on a fresh wound on a healthy oak, then that tree can become infected. Tree wounds can be made by man or nature, but nitidulid beetles are attracted to both.

Once established, the fungus moves from one tree to the next through common or grafted roots.

Interestingly, live oaks are somewhat intermediate between the two groups of oaks but are still very susceptible to the disease.

Prevention plays an important role in the management of oak wilt.  Landowners and homeowners can take an active role in oak wilt prevention by taking the following steps:

1. Avoid pruning or wounding oaks between February 1 and July 1. This is the time of the year when oak wilt fungal mats are most likely to form and the beetles are active.
2. Sterilize/Sanitize all pruning equipment between trees.
3. Immediately paint all wounds.
4. Do not transport or buy unseasoned firewood.
5. Promptly remove and either burn or bury all red oaks that are dying or have been recently killed by oak wilt.

Regardless of the reasons or time of year, proper pruning techniques should be used. These techniques include making proper pruning cuts and avoiding injurious practices such as topping or excessive crown thinning.  If you are uncertain about any of this information, you should consult with a Texas Oak Wilt Certified arborist, ISA Certified Arborist, or an oak wilt specialist from a city, county or state government agency such as the Texas A&M Forest Service or Texas A&M AgriLife Extension Service.

 

Sources:  Texas A&M Forest Service; Texasoakwilt.org

 

by Elaine Wilshusen, Somervell County Master Gardener

A favorite plant of mine is the Texas native, Symphyotrichum oblongifolium, known commonly as Fall Aster. It appears most of the spring and summer as a smallish dark green shrubby plant, disappearing into the background. However, after most other plants have stopped flowering, Fall Aster rewards the patient gardener by bursting into bloom with hundreds of 1″-sized purple flowers with yellow centers. It is deer resistant, plus bees and butterflies love it!

Fall Aster is a vigorously growing perennial, growing 2-3 feet tall with a spread of the same dimensions. It appreciates full sun but will tolerate part shade. Fall Aster will tolerate most soil types with good drainage and it is fairly drought tolerant. It is hardy to USDA Zone 4, making it a good choice for our North Central Texas winters. The top growth will typically die back after the first freeze of winter and can be pruned back at that time, if desired.

To keep the plants tidy and more rounded in shape, pinch back or trim them with scissors by no more than half in early June. This will also result in many more flowers in the fall.

Another great thing about Fall Aster is that they are so easily divided and passed along to others or planted in a new bed. I planted small, finger-sized divisions I dug up from my daughter’s garden last April. They appeared on the verge of death for a couple of weeks but then rebounded quickly. By June, they were already large enough to pinch back. Now, they are busily forming tiny buds getting ready to bloom in a few weeks!

Our first CHES (Community Educational Horticulture Sessions) meeting for the Fall season will  be held on Monday, September the 11th, at 6:30 pm, at a different location.  

We will meet at the Texas A&M Extension Office, 1405 Texas Drive, Glen Rose.

Shirley Smith and Donna Hagar will present a program on

Building a Rain Barrel and Harvesting Rain Water.

You won’t want to  miss this one!

 

As you may have read from last months newsletter, we have decided to try a new attempt (for us) to reduce weeds, pests and diseases from our gardens. This effort involves covering the beds with plastic and letting the sun ‘cook’ the soil to remove or reduce these garden plagues! The actual method is called soil solarization.

The process sounds simple enough. Remove plant debris, till the soil, cover with clear plastic, leave in place for 6-8 weeks to let the sun do its thing and voila – clean garden soil. This series of articles will document my efforts to achieve this gardening feat!

We are starting with 4 of our 8 large raised beds. So first effort was to clean out the beds. No small task as we started with a pretty big mess! But we persevered and got all of the old plant material out. This included a large comfrey plant, one entire bed of blackberries, a couple artichokes, cucumbers, melons, lots of elephant garlic, a few miscellaneous herbs, a tomato plant and a few peppers. And of course, an abundance of nut-sedge, bermudagrass, euphorbias and other lovely weeds and grasses! (the first two being a large part in the decision to tackle this project!)

Once cleaned out, my wonderful husband tilled 2 of the 4 beds while I was visiting family. We decided to experiment by not tilling the other 2 as a comparison (and save him the extra work!). Once cleaned/tilled, it was a simple matter of raking the beds smooth to make sure there were no rocks or sticks poking up that could puncture the plastic.

And then it was time! Time to cover with this ‘miracle’ plastic that is going to make our future gardening chores a breeze…..we hope! Now for the plastic. We are supposed to use ‘clear’ plastic. In my research, it was suggested to use 4 mil thickness. So after scouring the internet, I ordered a roll of 10’x100′ clear 4mil plastic. Some reviews indicated it wasn’t entirely clear but I was hopeful. FYI, I paid $30 for this roll. And no, it is NOT exactly clear! But it will have to do!

All of our beds are raised beds, so securing the plastic was a bit of a head scratcher. We knew that the plastic could easily tear using rocks and that 2×4’s may not be heavy enough in high winds. So we settled on making a channel just on the inside of the beds, put a layer of compost over the plastic in the channel and then laid t-posts on the compost for added weight. Works like a charm! One bed did not have the stone border so we were able to lay 2×6’s down on the plastic for that one and it is holding well.

It had rained the day prior to laying the plastic so we knew there was ample moisture, which is needed to help with the solarization process. Within an hour of laying the plastic, we noticed beads of water already accumulating on the plastic! This meant HEAT! Yay, we are on our way!

Or so we hope! One little problem has since arisen that we did not fully consider. While plastic retains the needed moisture UNDER the plastic, it also creates a bit of an issue on TOP of the plastic when it rains! Oops, so we now have a bit of a swimming pool in one of the beds! Hindsight says we should have mounded the soil better and fortunately it is in just 1 of the 4 beds. (We will leave this water during this Harvey induced rain spell and then I will make efforts to drain it.) I suspect this experiment isn’t over in teaching us many things!

 

Submitted by Merilyn Cranford, Somervell County Master Gardener

Another hot summer is almost behind us and everyone should be looking forward to cooler weather and Fall time.  However, those fantastic gardens that were planted last spring are now looking downright shabby.  Daylilies and hostas are starting to look tired, with yellowing foliage and spent bloom stalks.

But just because it’s nearly Fall doesn’t mean you have to give up on the garden and wait until spring to clean it up.  In fact, this colorful season offers some of the most pleasant weather for working outdoors.  It doesn’t take a lot of time and money to have a beautiful fall garden, but you need to get started by cleaning up what’s left over from spring before adding anything new for fall.

Cleaning up may not mean more work than a swift tug of the old plants for quick removal.  But if you’re more proactive and get to work while the old plants are still somewhat green, just snip tall stalks back with pruners.  Cut near the base of the plant, down to the foliage, to keep plants looking tidy.  With cleanup taken care of, you can see what holes need filling and go shopping.

Some suggestions for your consideration might be Hamelin fountain grass, Indian blanket, Pineapple sage (salvia), Chrysanthemum, Blue mist, Sedum, Mexican heather and other ornamental grasses.  Play with color, be creative and don’t be afraid to be different.  Also, don’t forget that fall is bulb planting and dividing time.

 

The Community Educational Horticulture Sessions have been suspended for the summer, but go ahead and mark your calendar for the second Monday in September, the 11th, at 6:30 pm, Citizen’s Center, Glen Rose.

Shirley Smith and Donna Hagar will present a program on Building a Rain Barrel and Harvesting Rain Water.  You won’t want to  miss this one!

Have a safe and wonderful summer.  Enjoy your garden!  August is a good time to stay inside where it’s cool and plan your winter vegetable garden.

by Julie Conner, Somervell County Master Gardener

If you are looking for a low maintenance colorful annual the Zinnia fits that bill.  They are a member of the Aster family which includes marigolds and the sunflower. Zinnias come in a variety of colors, flower head size and heights.

Zinnias do best in full sun and soil that has been enhanced with organic matter in a well-drained area.  Seeds can be planted directly in the bed after the last frost and covered with 1/4 inch of soil.  Water in well and when seedlings are coming up thin them to 6 to 12 inches apart depending on variety you have chosen.  The space between plants allows for air circulation which helps prevent any fungus growth.

Zinnias can be prone to black spot, rust and powdery mildew, but on the upside they attract beneficial insects, birds and butterflies.  Deadheading the blooms encourages more bloom growth.

To save seeds for next year’s planting simply allow the flowers to dry on the stem then store in a dry place.  Zinnias also make a great cut flower to bring indoors to enjoy.

by Linda Heideman, Somervell County Master Gardener

For the lawn and beds:

• Make sure the lawn is getting about 1-1.5 inches of water every week, watering between 2a.m.-6a.m. is ideal.
• Keep lawn mowed and landscaping weeded to prevent an infestation of chiggers.
• 
• Plant heat loving plants such as salvia, purslane, and portulaca.
• Water potted plants and baskets often – twice a day on triple digit days.
• Give plants a summer boost by fertilizing throughout lawn and beds.

For the garden:

• Check the garden daily and harvest veggies regularly for the best tasting and tender vegetables.
• All month long: Sow black-eyed peas, parsley, Swiss chard, and collards.
• Beginning of the month: Sow bush and pole beans, Irish potatoes
• Middle of the month: Sow cabbage and head lettuce.
• End of the month: Sow kale, spinach, and turnip seeds.
• Turn your compost pile.

Copied from the website of Ideal Partners Landscapes, Fort Worth