Ask a Master Gardener

Week

April 27^th - May 3^rd

Master Gardeners will be on hand at five nurseries on

Saturday April 30, 9-4 and Sunday  May 1, 1-4 to

answer questions and help you solve lawn and garden problems.

Colebroook Nursery

5915 W. 31st St

Tulsa, OK 74107

Sanders Nursery and Distribution Center

20705 E. 161st St

Broken Arrow, OK  74104

Southwood Landscape
& Nursery

9025 S. Lewis

Tulsa, OK 74137

Ted & Debbie's  

Flower & Garden

3901 S. Harvard

Tulsa, OK 74135

The Garden Trug Nursery  

& Gift Shop

3009 E. 101 St.

Tulsa, OK 74137

www.tulsamastergardeners.org 

918-746-3701

Garden Tour

Free Lawn & Garden Classes

Become a  

Master Gardener

Need more information?

Click on any of the links below:

4 Ways to
Contact Us

Forward to a Friend

May Lawn and Garden Tips   

• Plant warm season crops such as watermelon, cantaloupe, cucumber, squash, eggplant, okra, sweet potatoes and southern peas this month.
• Plant both your summer bulbs-such as cannas, dahlias, elephant ear, caladiums and gladiolus-and your tropical annual flowers, such as periwinkles-when the soil temperaturewarms to 65 to 70 degrees. This is usually during the last half of May. The Mesonet web site has current soil temperatures.
• Bagworms may appear on junipers (including eastern red cedars) and Arbor vitae in late May. An organic botanical pesticide containing Bacillus thuringiensis (Bt) is safe and effective applied by early June.Click here for more.   
• Lacebugs may appear on azaleas this month. Call Master Gardeners at 918-746-3701 for control recommendations.
• If azaleas or any spring blooming plant needs pruning, do so immediately after blooming. If fertilization is needed, this is also a good time to apply according to the label.
• Seeding of warm season grasses such as Bermuda and zoysia are best done from mid-May through June. This allows time for root systems to develop in summer before winter dormancy. 
• If you did not fertilize your cool-season grasses like fescue in March and April, do so now. Do not fertilize these grasses again until fall.
• Fertilize Bermuda and zoysia lawns regularly from April to late August, according to OSU's Bermuda Maintenance information sheet referenced below.
• Be sure to keep your newly planted trees well watered.  And don't forget to mulch around them.The mulch should be placed like a donut, not a volcano.
• Recycle those nursery pots from spring planting. Nurseries accepting used pots for recycling are Colebrook, Riddles, Ted and Debbie's, Sanders and Southwood, and Lowes.
• Clean out water gardens and divide plants. Begin feeding fish when the water temperature is above 50 degrees.
• Fruit trees need regular spraying for insects and disease this time of year. Click here for a complete fruit tree spraying schedule.   

Q&A

Ask a Master Gardener

By Karen Watkins

I have a 10X20 plot of Bermuda that is mostly all        weeds and dirt, where do I start?

This is a great time of year to totally make-over a small area of Bermuda lawn.  To begin again, start with using a gyphosate product on a calm day and repeat application after ten days if needed.  Glyphosate is non-selective and will kill any grass or weeds.  Rake up weed debris and then prepare the bed by rototilling the soil, adding a lawn starter fertilizer and compost product if needed. The fertilizer nutrients used are best based on a soil test (see instructions at MG web site).  Lay Bermuda sod or seed in May and into mid-June. This warm season grass needs the rest of the summer to establish a root system before winter dormancy.  Water often to keep the soil moist until growth begins, then water less frequently and more deeply. After establishment, Bermuda needs at least 1" of water per week in summer. Begin mowing at 2 inches. Fertilize twice more during the summer and up to the first of September according to OSU's Bermuda Turf Maintenance Schedule linked below.   

I am seeing more dandelions than usual in my lawn, is it too late to use a preemergent herbicide?

The rains we received recently have brought about a flush of weed growth. Weeds such as dandelions, are flourishing.  Preemergent herbicides will not have any effect, of course, on weeds that are already up and growing, a postemergent preparation containing 2-4-D, such as Trimec would be appropriate for these actively growing broadleaved weeds. Preemergents are used in the early spring mainly to prevent crabgrass but also are effective for spring germinating broadleaved weeds. These herbicides should be applied in the window between mid-February and mid-March.  Remember to water in with at least � inch of water, otherwise it is totally ineffective. For complete coverage of crabgrass germination, some preemergent products recommend a second application 60 days after the first. Read and follow labeled directions.

Many of our large trees, bark diameter of forty inches, are showing signs of stress and leaves are small and looking brown, what can we do?

Since you did not specify any one type of tree, I am assuming that many of your larger trees are showing signs of stress. We have not had significant rainfall since September of last year. The heavy snows of winter did not add much moisture. It was a very dry snow, but it did insulate the lower parts of plants and probably prevented some winter-kill.

 Large trees require more irrigation than what the homeowner's irrigation system often provides. If your trees appear drought stressed, place a hose beneath a large tree and allow it to run on very low pressure until the ground is soaked to several inches. Try to wet the whole root zone under the trees canopy and observe to see if there is a noticeable benefit to the tree. 

I saw a hardy kiwi vine at the nursery and wondered if it would grow here?

Hardy kiwi vine, Actinidia arguta, is a perennial and hardy to zone 5. It will grow in our area.  Kiwifruit have separate male and female plants, both are needed for successful pollination and fruit set. The fruit is small with a smooth skin and is produced late in the summer.  Kiwi will not produce fruit until the vine is 3-4 years old. After fruiting begins, they should be productive for many years.  Kiwifruit must have very strong, permanent trellises to hold up the vines, such as the T-bar or pergola trellis.  Full sun to light shade is required and well drained acidic soil.  The main reason for kiwifruit failure in the first year is poorly drained soils or lack of water in well-drained soils.  Click here for OSU Fact Sheet HLA-6249). 

Increasing Tomato Odds!  By Jackie Rago

There's nothing quite like the perfect juicy red tomato. You can smell summer in that bite of the first truly vine-ripened tomato as it explodes your saliva glands. The juice drips down your chin, down your arm, onto your clothes, the taste so sublime it doesn't matter about your shirt.

Whether you prefer to slather your tomato in mayonnaise, sprinkle sugar on it, salt and pepper it, layer it with mozzarella, basil and balsamic vinaigrette, slap a slice on a burger, dice it for salsa, make bruschetta, puree it into a marvelous sauce, mate it to an avocado with red onion - there are a hundred and one ways to use a juicy tomato. It's not an accident that tomatoes are the most popular homegrown vegetable.

There are any numbers of ways, when bitten by the 'grow your own' bug, to integrate tomato plants into your landscape. Whether in an apartment, your own home, or in a community garden there are four basic factors in growing any plant with success: light, temperature, water, and nutrients.  

The first step in achieving that perfect tomato is determining where you can expect full sun and then create your planting area there- be it in a pot, a raised bed, hanging from a rafter or from a shepherd's hook.  

The second step in insuring your success is planting at the proper time of the year, when the soil temperature is above 60�F. You can check the Mesonet website for soil temperatures in your county. You may also plant tomatoes in July for fall gardening as the seedlings do well in the heat with adequate water. Our growing season is long enough to have tomatoes right up to the first killing frost, in Tulsa typically the first week of November. Any green tomatoes remaining can be picked and stored until ripe.

The third step is to have your garden soil tested to discover the nutrient content of the soil. Call the Tulsa County Master Gardeners for the "how-to": 918-746-3701 or visit www.tulsamastergardeners.org. This will tell you the percentage of nutrients already in the soil and what kinds of soil additions are needed to bring the pH to optimal growing conditions. As a general rule add 2 inches of compost or organic humus, mixing it into the top 6 inches of soil. A slow-release all purpose vegetable fertilizer will keep fertility levels even for several months. The mystery numbers on the fertilizer bag- the N-P-K- indicate the nutrient percentage. Nitrogen is the nutrient which promotes green foliage and tall growth. Phosphorus and potassium are Important for general health, including flower and fruit development.

The fourth step is planning adequate and consistent watering, especially during Oklahoma summers. Plant the tomatoes slightly deeper than they originally grew, in the evening or on a cloudy day to prevent wilting and drying out. Water during the day when there is adequate time for the plants to dry to prevent disease growth. The tomatoes will need at least an inch of water per week in May and June and 2 inches or more per week in July and August. It's also recommended to mulch around the tomato plants to help conserve moisture, stop weed growth, and prevent soil from splashing on the leaves and spreading fungus and disease. Fungus and bacteria live in all garden soils and will thrive in the right conditions.  Consider Earth-Kind gardening and investigate drip irrigation in order to conserve and use water most efficiently.

You will also need to stake or support the tomato plant during its growth. The kind of support depends upon the kind of tomato. Be aware that 'determinate' tomatoes will bear fruit all at once and generally have more of a bush shape. An 'indeterminate' tomato, a vine type, will bear fruit all season until frost kills the vines. It can grow in excess of 10 feet.

The final consideration is picking the right tomatoes. Once you have all the supporting conditions perfect, make sure your tomato plants are resistant to common Oklahoma problems of wilt and nematodes. After all you've just spent all that time, effort, and expense to grow the perfect tomato. Don't lose it to something that could have been prevented, if you'd only known.

OSU fact sheet HLA-6012, GrowingTomatoes in the Home Garden lists disease resistant varieties, good growing practices and sound advice for increasing your odds.

Crape Myrtles: Great Summer-Long Color By Dianne Nail

The woody shrub that is the 'flowering' queen of summer has to be the crape myrtle, Lagerstroemia indica. The hotter the summer becomes, the more prolific the crape myrtle blooms, sometimes up until the first frost. It comes in many sizes and an array of colors. Hybridizers are continually improving the species by creating longer periods of bloom, larger flowers and colorful foliage.

When choosing this super shrub, match the size to location. Crapemyrtles come in 4 basic sizes-standard at 15-20 feet, semi-dwarf at 5-8 feet, dwarf up to 4 feet and miniature at less than 2 feet. In addition to the attractive blossoms, which is the Tulsa area's main color in summer, older plants often have very appealing exfoliating bark, an asset in all seasons. Some of the varieties also have colorful leaves in fall as an added bonus.  Click here for a list o over 100, by size and color.

Establishment and care of crapemyrtles is usually not a problem. We are at the northern-most range of their cold hardiness and some winterkill may occur in unusually cold winters. The good news is that these shrubs rapidly recover and both regrow and bloom in the following season. Powdery mildew on the foliage may be a problem. This is usually cultivar specific. If it recurs on a particular plant, preventative antifungal sprays are available, but it may be best in the long run to replace the susceptible plant with a disease resistant variety.

Do not prune crapemyrtles without a reason. Many people over-prune either because their neighbor does it or they mistakenly think it increases numbers of blossoms. If the proper plant is selected for the area, no pruning is needed. If you do prune remove only the terminal foot or so of limbs in late winter or early spring before new growth begins. Click here for complete pruning guidelines for shrubs.

After making your selection of crape myrtle based on color, disease resistance, and height matched for the location, sit back and enjoy the splash of color all summer long, brilliant fall color, and interesting silky sculptural trunks in winter.