Sunday, May 13, 2018 0 comments By: Jack Downer

Attracting Monarch Butterflies to Your Garden

Attracting Monarch Butterflies to Your Garden
Brian Jervis: Ask a Master Gardener
Sunday, May 13, 2018
Q: I am intrigued by the beautiful butterflies that are around Tulsa each year but know very little about them. Could you tell me how I can attract them to my garden? Melissa H., Tulsa
A: Most of us would agree with you that butterflies are such a visual blessing to our gardens. They are beautiful and do wondrous work in the pollinating world. Two of the most common types of butterflies in our area are monarchs and Black Swallowtails (the Oklahoma state butterfly).
Food is obviously an essential part of their life cycle, but they are somewhat picky eaters and will feed exclusively on particular plants, called host plants. Having these plants available will not only draw butterflies in to lay their eggs, but also will allow you to watch the development of the caterpillars. One of the keys to having beautiful monarch butterflies around your garden is having lots of milkweed. Monarch caterpillars feed exclusively on milkweed (Aesclepias) and cannot survive without it. With almost 20 different species of milkweed native to Oklahoma, you’re sure to find some that fit your garden area. When planting milkweed, be sure to plant multiples (three to five or more). A single plant simply will not be sufficient for monarchs as they are eating machines. If you want lots of monarchs, plant lots of milkweed. Planting milkweed is a great way to help other pollinators too, as the plant provides valuable nectar resources to a diverse suite of bees and other butterflies. Other nectar sources include marigolds, petunias and asters. While milkweed is a beautiful plant to look at, be sure to keep milkweed sap out of your eyes as it can be irritating. Caterpillars of the Black Swallowtail feed on parsley, dill and fennel. So, if you garden with these, plant enough for you and the caterpillars.
A few key tips to coax these beauties to your yard include providing “roost” stations for them at varying heights and protection to shield them from wind and predators. They are attracted to plant color, structure and height. Provide moist areas with shallow puddles to encourage gathering. Butterflies are cold-blooded and enjoy warming themselves in the sun so provide rocks or exposed soil that will warm to the sun’s exposure. Use few, if any, insecticides as they can easily kill good insects, along with bad ones, and no bug zappers please.
Because of modern changes, habitat destruction and shifting land management practices (suburbanization), there is a lot less milkweed today than previously. This has caused a decline in monarch butterfly populations and numbers to be at an all-time low for the past two overwintering seasons. Many pollinators are declining as well. By planting milkweeds and nectar plants for adult monarchs and pollinators, you can help maintain the monarch migration and sustain the pollinators whose pollinating services maintain our ecosystems. is a terrific resource to learn more about monarch butterflies and milkweed. Also, consider attending a free seminar called “Monarchs, Milkweeds and More” on May 26 at the Tulsa fairgrounds, hosted by the Tulsa Master Gardeners. Detailed information can be found at
Garden tips

• Clean out water garden and prepare for season. Divide and repot water garden plants. Begin feeding fish when water temperatures are over 50 degrees.
• Plant warm-season vegetable crops, such as watermelon, cantaloupe, cucumber, eggplant, okra, sweet potatoes, etc., now.
• Fruit trees, especially apples and peaches, must be thinned out for best production. Prune apples 4-6 inches apart and peaches 6-8 inches. This will ensure larger fruit and less damage to limbs. If not thinned, the tree's resources will be used to such an extent that next year’s crop will suffer.
• Late May is the best time to control borers in the orchard. Contact OSU Tulsa Master Gardeners for fruit tree spray recommendations.

Sunday, April 29, 2018 0 comments By: Jack Downer

Attracting Hummingbirds Using Feeders and Flowers

Attracting Hummingbirds
Tom Ingram: Ask a Master Gardner
Sunday, April 29, 2018
Q: I am starting to see hummingbirds. How can I attract them to my garden and take better take care of them? DJ
A: Humming birds are the smallest of native birds in North America and are typically about 3½ inches in length, weighing only about ¼ of an ounce. As most of us know, the humming sound is created by their wings, but did you know they average about 55 strokes per second?
During courtship, males can exhibit rather dramatic behaviors by ascending and then diving straight down toward either the object of their affection or irritation. When this happens, their wings can beat up to 200 beats per second, which creates a louder than normal humming sound, as well as a colorful display of their feathers.
While many people think hummingbirds use their tongues as we might use a straw to drink, they actually drink via a licking motion at a rate of about 13 licks per second. Hummingbirds also capture small flying insects in the air, especially when raising their young.
All hummingbirds of North America are migratory with the exception of one species found in California. The species found most often in Oklahoma is the ruby throated hummingbird. This hummingbird may travel more than 2,000 miles during migration, including 500 nonstop miles over the Gulf of Mexico. To make this journey, they must add about half of their body weight in fat before the trip.
With all the energy expended during flight apart from migration, hummingbirds must feed every 15 minutes during the day to survive. So, the best way to attract them to your garden is through nectar-producing plants or by providing a supplemental food source. Placing the feeder near your garden will encourage feeding from natural sources.
When placing feeders near the house, be sure to get several feeders and place them some distance apart as hummingbirds can get territorial and aggressive around a single food source. Also, be sure to use a feeder with a bee and wasp guard, as this will eliminate aggressive competition for nectar between these insects and the hummingbirds. There is no need to be concerned with small insects found at the mouth of the feeder, as they will typically help fulfill the hummingbird’s need for protein.
You can make your own feeding solution using one part granulated sugar to four parts boiling water. Of course, cool the solution before pouring it in the feeder. The use of red food coloring in the solution is unnecessary and unhealthy for the birds. Feeders should be cleaned every two to three days, especially during warm weather.

Garden tips
  • Prune and feed all of the spring-blooming shrubs, such as azaleas and forsythia immediately after blooming, if needed. Azaleas need less fertilizer than many shrubs and often a yearly addition of mulch, as it decays, it will add all the nutrients they need.
  • Cool-season lawns — tall fescue and bluegrass — can be fertilized again. If you did not fertilize in March and April, do so now. Do not fertilize these grasses in summer.
  • Seeding and sodding of warm-season grasses, such as bermudagrass, Buffalograss and zoysiagrass, is best performed in mid-May through the end of June. The soil temperatures are warm enough for germination and growth. These grasses need a long summer growing season to promote winter hardiness.

Sunday, April 15, 2018 0 comments By: Jack Downer

Tomato Growing Tips

Tips on Growing Tomatoes in Oklahoma
Allen Robinson: Ask a Master Gardener
Sunday, April 15, 2018
Q: My family loves to eat fresh tomatoes off the vine, but my friends tell me they have trouble growing tomatoes around here. Can you tell me why it is difficult to grow tomatoes here and what I can do about it? Tracy A., Tulsa
A: You are certainly not alone when it comes to loving tomatoes fresh off the vine, as well as having trouble growing them in northeast Oklahoma.
One of the most common issues is known as “blossom drop,” which occurs from poor pollination. Weather is the chief cause of inadequate pollination in garden-grown tomatoes, with the most important factor being temperature. Effective pollination stops occurring once night temperatures are consistently over 70 degrees and/or when daytime temperatures are consistently over 92 degrees, especially if it is windy. Too much rain or too high or low humidity are additional weather factors that reduce pollen fertility. Also, over application of nitrogen fertilizer leads to blossom drop, as well as tall, lanky plants.
The solution to this is to plant healthy plants as soon as possible after the last frost has occurred. Then, pick the fruit as soon as it turns pink and let it continue to ripen indoors. Do not let it sit on the vine until it becomes overly ripened and soft.
Another common issue is called “blossom end rot,” where the fruit develops blemishes on the blossom end of the fruit. This is caused by a calcium deficiency in the plant when the fruit is young. Overwatering, either from nature or the gardener, is the most common cause rather than the lack of calcium in the soil.
Skin splitting, called “cracking,” is also caused by plants going from too little to too much water. Be consistent about watering. Mulch plants to provide consistent moisture at the root level, but do not mulch directly against the plant as it can lead to diseases.
Speaking of diseases, avoid splashing soil upon the plant and onto tomato fruits, as this carries related fungi and bacterial diseases. Instead, either use a soaker hose or drip irrigation system or carefully water at the base of the plants. Avoid damaging tender roots by not hoeing too deeply or too closely to the plants.
In addition, several pests love to live off the stems and leaves of tomato plants. For a listing of pests and how best to battle them, go to and search for OSU Fact Sheet EPP-7313 (Home Vegetable Garden Insect Pest Control).
Experts say the best weed control in a lawn is to simply grow a healthy lawn. The same is true for vegetables. Look for high quality varieties at reputable nurseries around town and ask which varieties are the most disease resistant. Several varieties are available.
Tulsa’s climate is a challenge to growing tomatoes in the summer but, with a little attention to details, you can have good success. And, remember, there’s always fall.
Garden tips

Fruit and Nut
 Don’t spray insecticides during fruit tree bloom or pollination may be affected. Disease sprays can continue according to schedule and label directions.
 Control cedar-apple rust. When the orange jelly galls are visible on juniper (cedar), following a rain, begin treating apple and crabapple trees with a fungicide.
 Fire blight bacterial disease can be controlled at this time. Plant disease-resistant varieties to avoid diseases.
 Continue spray schedules for disease-prone fruit and pine trees.
Trees and shrubs
 Proper watering of newly planted trees and shrubs often means the difference between success and replacement.
 Remove any winter-damaged branches or plants that have not begun to grow. Prune spring-flowering plants as soon as they are finished blooming.
 Control of powdery mildew disease can be done with early detection and regular treatment. Many new plant cultivars are resistant.
 Leaf spot diseases can cause premature death of foliage and reduce plant vigor.
 Most bedding plants, summer-flowering bulbs and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low 60s.
 Harden off transplants outside in partial protection from sun and wind prior to planting.
 Let spring -flowering bulb foliage remain as long as possible before removing it.
 Wait a little longer for it to warm up before planting cucurbit crops and okra.
 Plant vegetable crops in successive plantings to ensure a steady supply of produce, rather than harvesting all at once.
 Cover cucurbit crops with a floating row cover to keep out insect pests. Remove during bloom time.
 Watch for cutworm damage and add flea beetle scouting to your list of activities in the vegetable garden.
 Hummingbirds arrive in Oklahoma in early April. Get your bird feeders ready using 1 part sugar to 4 parts water. Do not use red food coloring.
 Keep the bird feeder filled during the summer and help control insects at the same time.
 Lace bugs, aphids, spider mites, bagworms, etc. can start popping up in the landscape and garden later this month. Keep a close eye on all plants and use mechanical, cultural and biological control options first.
 Be alert for insect pests and predators. Some pests can be hand-picked without using a pesticide. Do not spray if predators, such as lady beetles, are present. Spray only when there are too few predators to be effective.
 Warm-season grass lawns can be established beginning in late April from sprigs, plugs or sod.
 Fertilizer programs can begin for warm-season grasses in April. The following recommendations are to achieve optimum performance and appearance of commonly grown species in Oklahoma.
  • Zoysiagrass: 3 pounds nitrogen per 1,000 square feet a year
  • Buffalograss: 2-3 pounds nitrogen per 1,000 square feet a year
  • Bermudagrass: 4-6 pounds nitrogen per 1,000 square feet a year
When using quick-release forms of fertilizer, use 1 pound of actual nitrogen per 1,000 square feet per application; water in nitrate fertilizers.
 Mowing of warm-season lawns can begin now. Cutting height for bermudagrass and zoysiagrass should be 1 to 1½ inches high, and buffalograss 1½ to 3 inches high.
 Damage from Spring Dead Spot Disease (SDS) becomes visible in bermudagrass. Perform practices that promote grass recovery. Do not spray fungicides at this time for SDS control.
 Grub damage can be visible in lawns at this time. Check for the presence of grubs before applying any insecticide treatments. Apply appropriate soil insecticide if white grubs are a problem. Water product into soil.

Sunday, April 1, 2018 0 comments By: Jack Downer

Bradford Pear Trees are Very Invasive and Short Lived

White Flowering Bradford Pears Have a Dark Side

Brian Jervis: Ask a Master Gardener

Mar 31, 2018

Q: What are these beautiful trees I am seeing all over town with the white blossoms? TP
A: You are probably referring to the Bradford pear. While they are beautiful and quite popular, they have a dark side. But first, let’s talk about what they are and how they got here.
The Bradford Pear (Pyrus calleryana “Bradford”) was first introduced to the United States in the early 1900s as a way to help control fire blight of the common pear. By the ’80s, it had become the second-most popular tree in America, primarily as an ornamental tree.
The Bradford grows rapidly (12- to 15-foot increase in height over an 8- to 10-year period), to a height of 30 to 50 feet tall and 20-30 feet wide with a short to moderate life span of 15 to 25 years (less if we get an ice storm).
Most people are attracted to the Bradford Pear for its showy white flowers that appear in spring. The flowers are beautiful but, unfortunately, have an unpleasant fragrance. Early spring flowering can last two weeks, but late frosts may reduce bloom time.
Sounds like a great tree. Well, that’s what many of us thought until we got to know its dark side.
Although the Bradford pear was originally bred to be sterile and thornless, they easily cross-pollinate and produce fruit. These fruits are like tiny, hard apples, round, ½-inch in diameter, greenish-yellow flecked with whitish spots, inedible, with 2-4 black seeds. After it freezes in the fall, the fruit softens and becomes palatable to birds that help spread the tree.
Unfortunately, these offspring revert back to the thorny variety of their origin. They are not usually noticed until spring when we see them along the highways. These descendants are also quite invasive and tend to displace native plant communities, disrupting natural succession. All those white-blossomed trees you are seeing outside the fence line of the highway are likely the thorny offspring of the Bradford pear.
So, what do we do in response to what we now know about the Bradford? In spite of the fact that Bradford pear trees are well adapted for Oklahoma climatic conditions, just say no. There are a variety of other trees that work well in Oklahoma without the Bradford’s invasive side effects. They are also quite weak, making them poor choices to deal with Oklahoma winds and ice.
If you have a Bradford pear, you might need to consider replacing it, and if you are looking for a spring-flowering alternative, you should consider a redbud or dogwood tree. For more information on which types of trees do well in Tulsa, visit the Hot Topics section of our website,, and download a copy of our info sheet: “Trees for Tulsa.”
Garden tips
  • Most bedding plants, summer-flowering bulbs, and annual flower seeds can be planted after danger of frost. This happens around mid-April in most of Oklahoma. Hold off mulching these crops until spring rains subside and soil temperatures warm up. Warm-season annuals should not be planted until soil temperatures are in the low 60s.
  • Don’t plant tomato sprouts too early. The soil temperature is key and should be above 60 degrees before planting. If the soil is too cool, the plants will sit there and not grow. Remove the blossoms from any tomato plant at the time of planting; it needs roots before making tomatoes.
  • You can find some wonderful tomatoes, herbs and flowers for your garden by shopping online during our plant pre-sale. This is the last week of the sale. Visit our website,, for information.

Sunday, March 18, 2018 0 comments By: Jack Downer

Oklahoma Proven Selections for 2018

Master Gardener: Plants Proven to Grow Well in Oklahoma
Allan Robinson: Ask a Master Gardener
Sunday, March 18, 2018
Q: I want to invest in and plant plants that I know will do well in the Tulsa area, given our weather extremes. Is there a good way to know what grows well in our area? Sally M., Tulsa
A: This is a good question that many people think about. And it’s a reasonable request given the amount of labor involved in planting, as well as the cost of landscaping products these days. So, wouldn’t it be nice if someone had already done the research on which plants do best in our neck of the woods given our sometimes rather erratic weather conditions? And also tell us where to plant them so they have the highest chance of success? They have!
It’s called the Oklahoma Proven Program. Oklahoma Proven is an annual plant evaluation and marketing program coordinated by the Department of Horticulture and Landscape Architecture at Oklahoma State University. Designed to help consumers select the best plants for Oklahoma gardens, these plants are tolerant of the varied and difficult environmental conditions found throughout Oklahoma.
Every year, an annual, a perennial, a shrub and a tree are selected. So, the selections for 2018 are:
Annual — Supertunia Vista Bubblegum: a vigorous, self-deadheading petunia that requires little care once established. Their spectacular color can spill over the edge of a container or retaining wall or spread out in a flower bed. Exposure: Full sun to part shade. Soil: Moist, well-drained soil.
Perennial — Versatile Indian Pink: Also called Woodland Pinkroot, it is a native species to the southeastern United States. It grows in shady gardens or sunny locations. It prefers moist soils and is drought-tolerant once established. Use Indian Pink in a woodland garden, perennial border, rain garden or native garden. Exposure: Sun to part shade. Soil: Moist or dry soils. Hardiness: USDA Zone 5-9.
Shrub — Bush Clover: a hardy, semi-woody, deciduous shrub that can reach 4 to 6 feet high and at least as wide with arching stems. Rosy-purple flowers develop on new wood in late summer to early fall. Exposure: Sun to part shade. Soil: tolerates poor, infertile soil, but excellent drainage is essential. Hardiness: USDA Zone 6-10.
Tree — Zelkova Serrata: a deciduous tree with a vase-shaped habit that typically grows 50-80 feet tall and most often occurs in rich, moist woods and hillsides. It is noted for its graceful shape, clean foliage, attractive bark and resistance to Dutch Elm disease. Exposure: Full sun or light shade. Soil: Tolerates wide variety of soils. Hardiness: USDA Zone 5-8.
Note: The Greater Tulsa metropolitan area is in USDA Hardiness Zone 7A, which equates to an average low temperature of 0 to 5 degrees.
The Oklahoma Proven program has been in existence since 1999 and the best part is that you can find every year’s selection back to 1999 online at
Remember that all plants need special attention during the establishment phase or during periods of environmental extremes, which we have been experiencing more of in recent years.
Nothing is guaranteed, but you can improve your odds significantly by choosing Oklahoma Proven varieties.
Garden tips
  • If you had previous damage to the tips of pine tree limbs, especially non-native pines, it may be diplodia tip blight (a fungus) or Nantucket pine tip moth damage. Both are controlled with pesticides starting this month. Call the Master Gardener office at 918-746-3701 for recommendations.
  • Pre-emergent herbicide to control crabgrass and other summer weeds should be applied by the middle of March.
  • Divide, share with friends and replant overcrowded summer- and fall-blooming perennials.
  • One of our most anticipated events is currently underway: The Tulsa Master Gardener Spring Plant Sale. You can choose from 211 plants, including annuals, perennials, grasses, herbs and tomatoes. To shop online or find out more information on any of these programs, visit our website at

Saturday, March 10, 2018 0 comments By: Jack Downer

Prune Crapemyrtles in Late Winter, But Avoid "Crapemurder"

How not to commit 'crapemurder' on your crapemyrtles this spring

Brian Jervis: Ask a Master Gardener

Saturday, March 10, 2018

Q: How and when should I prune my crapemyrtles?

A: Crapemyrtles, along with all trees and shrubs, should only be pruned for a reason. The best time to prune these and other trees and shrubs is late winter or early spring, before leafing out. An exception to this time are the spring-blooming shrubs, such as azaleas and forsythias, which should be pruned after blooming, if needed. Delaying pruning of spring-blooming plants is only to preserve the flower buds formed the previous year.
There is a common belief by many that crapemyrtles should be pruned back to an ugly set of horizontal nubs in the spring time. Nothing could be further from the truth about good crapemyrtle care. Crapemyrtles should be allowed to let nature have its way and to grow to their full height.
Some people think that blooming will be increased by drastic pruning (many horticulturists call this “crapemurder”), but Dr. Carl Whitcomb, a retired OSU professor and developer of crapemyrtle cultivars, cites evidence that blooming is less, not more, with drastic pruning. Light pruning of endmost 12-18 inches, back to a lower limb, can increase numbers of blossoms. However, these plants were engineered by nature to bloom profusely without this type of pruning. In summer, one can promote a second wave of blossoming by pruning off old blossoms after they fade.
Reasons to prune crapemyrtles are to confine it to the space available or to improve the shrub’s shape and structure. Removal of dead or diseased limbs and elimination of internal crossing branches should be done anytime.
For those plants that are too big for their space, rather than trimming them back each year, consider removal and planting one of the smaller crapemyrtle cultivars. There are many sizes available, ranging from 18 inches to 25 or more feet when mature.
One question that sometimes arises relates to the seed pods left over in fall after blooming is completed. The plant will remove them naturally as they have been doing for thousands of years, and they need no pruning.
Another pruning suggestion one should consider with crapemyrtles concerns those plants with a multitude of trunks. These are best reduced to three to five trunks, which will not only have more curb appeal, but also will allow more energy to be directed toward further growth and blossom formation. To further improve appearance of these shrubs, consider removing the limbs from the lower third or half of the trunks.
Crapemyrtles are notorious for sending up shoots or sprouts from the base of the plants, especially in the spring. These should be removed by pulling off if able, or clipping close to the ground, if needed.
We have an advantage over our northern neighbors in being able to grow these magnificent plants, which are the mainstay of color in Tulsa during the summer. They deserve the best care we can give them, they should not be subjected to “crapemurder.”

Garden tips

  • Now is a good time to cut back your perennial ornamental grasses, such as pampus grass. Cut back to remove the dead grass, but avoid damaging new buds and early green growth at the base.
  • Begin planting blackberries, raspberries, strawberries, grapes, asparagus and other perennial garden crops this month. Contact Tulsa Master Gardeners at 918-746-3701 for specifics about these plants.

Sunday, March 4, 2018 0 comments By: Jack Downer

Guidelines for Planting Vegetables in Springtime

Spring Vegetable Planting
Tom Ingram: Ask a Master Gardener
Sunday, March 04, 2018
Q: When can I start my vegetable garden? MA
A: Oftentimes, people will suggest certain dates when you can plant your vegetable garden. But dates are only guidelines. To know for sure when you can plant, we must look at the weather and do a little investigation to determine soil temperature.
For example, oftentimes people will say St. Patrick’s Day is when to plant potatoes. There is no potato magic in St. Patrick’s Day, other than in a normal year you are probably OK planting on this day. The truth about when to plant is based on the best soil temperature for planting potatoes.
According to the OSU Extension, soil temps need to be above 50 degrees before we plant potatoes. At the writing of this article, soil temps are hovering around 46 degrees. So, we are getting close, and if the weather continues on as we expect, we will likely have a soil temp above 50 degrees by St. Patrick’s Day. But give us a few warm days and an expectation that spring is on the way and we could plant them sooner.
Peppers are easy to grow in Oklahoma and have the benefit of being a versatile crop. However, peppers are sensitive to temperature. Air temperatures of below 60 degrees or above 90 degrees can prevent fruit set, which can limit the growing window in Oklahoma.
So, how do Oklahoma gardeners get around this? Because cold soils do not encourage germination, it is common for gardeners to start seeds indoors so they will be ready to go when it warms up.
If you have been to any of the garden centers in northeast Oklahoma recently, you will have noticed racks of seeds and seed-starting supplies. Many of us have already gotten our seeds started and can’t wait to get these little ones in the ground.
But the time to plant these transplants still depends on soil temperature and when the danger of a freeze has passed. In northeast Oklahoma, we typically say that date is April 15. Many of us have a hard time waiting that long and tend to plant before that date. However, if you do, you should be ready to cover your plants if a late-season snow arrives.
Now, you may be saying, all this talk about soil temperature, how am I supposed to know that? In Oklahoma, we have a wonderful resource called the Mesonet. The Mesonet is a joint project between OU and OSU with at least one weather-monitoring station in each county.
You can visit for an abundance of weather information, including rainfall and soil temperatures. We also have an abundance of resources on our website to help you grow better vegetables.
Garden tips
  • Our yearly Urban Gardener classes begin March 15. Topics include plant botany, soil, growing fruits and vegetables, flowers, trees and shrubs, and turf.
  • We will also be conducting our educational Lunch & Learn classes at the Tulsa Central Library downtown beginning March 20.
  • One of our most anticipated events is currently underway: The Master Gardener Plant Sale. You can choose from 211 plants including annuals, perennials, grasses, herbs and tomatoes.
  • To sign up or find out more information on any of these programs, visit our website,