Extension

Spring Fertilization Tips for Oklahoma Lawns

Mingying Xiang, PhD, Professor of Turfgrass Science / Turf Extension Specialist

Spring seems to have arrived a bit ahead of schedule across Oklahoma this year. While the warmer temperatures are certainly welcome, they can create a false sense of urgency when it comes to lawn care. It's important to stay on track with proper seasonal timing, especially for fertilization.

Know Your Soil Before You Fertilize

Before we talk about fertilization, it's always good to know what nutrients your soil actually needs by conducting a soil test, especially if you haven't done one in a couple of years. For more information on how to conduct a soil test, please refer to Factsheet ID: L-249.

Warm-Season Turfgrasses

(Bermudagrass, Buffalograss, Zoysiagrass)

Even though your lawn may be starting to show some green, now is not the time to fertilize warm-season grasses. Early nitrogen applications can do more harm than good by:

• Encouraging premature leaf growth before roots are fully active
• Depleting stored energy reserves
• Increasing susceptibility to late-spring cold snaps

Best practice: Hold off on fertilization until early May, when the turf is fully green and actively growing. This ensures the plant can efficiently use nutrients to support both shoot and root development.

Cool-Season Turfgrasses

(Tall Fescue, Kentucky Bluegrass, Perennial Ryegrass, etc.)

Cool-season grasses are already responding to the early warmth and may be actively growing. While fall remains the most important fertilization window, a light spring application can be beneficial:

• Apply 0.5 to 1.0 lb of nitrogen per 1,000 sq. ft. if turf appears thin or lacks color
• Avoid heavy applications, which can promote excessive leaf growth, increase mowing frequency, and stress the plant as temperatures rise later in spring

Best practice: Keep spring fertilization light and focus on maintaining turf health without overstimulating growth.

Summary

Patience, especially with warm-season grasses will lead to healthier, more resilient lawns as we move into the growing season. For more information, please refer to Factsheet HLA-6420.

Cutworms in the Home Garden

Shelby Mendoza, OSU Student Farm Assistant Manager

As you begin planting your seedlings, you may notice leaves lying on the ground next to your plants or the tops of your seedling seemingly cut off and lying nearby. These are common signs that cutworms may be present in your garden.

About Cutworms

• Larval stage of various moths in the Noctuidae family that are dull colored, typically black, grey, and tan
• General feeders that attack wide range of plants, from turf to vegetables
• Nocturnal; they feed at night and hide under debris or in the soil during the day
• Tend to curl into a “C” shape when picked up or disturbed
• At least eight species found in Oklahoma

Cutworms damage plants by curling around the stem and feeding near the soil surface, causing the plant to appear as though it has been cut off at the base. They may also feed on leaves, cutting them off where the leaf meets the stem

Control Options

There are several methods to control cutworms in your home garden.

• Collars: A physical barrier to protect seedlings, which are the most vulnerable to cutworm damage. Collars can be made by cutting the bottoms out of plastic cups (as pictured), using a cleaned can that has both ends removed, or by repurposing cardboard tubes from paper towels or toilet paper rolls. Place the collar around the base of the seedling and bury it slightly in the soil, ensuring the soil is firm around the base to prevent it from blowing away. These collars only need to remain in place while plants are small and most susceptible to damage.
• Spinosad: A naturally derived insecticide from soil bacteria that controls caterpillars through ingestion or contact. While it does not cause immediate death, it stops caterpillars feeding and eventually leads to death. Because it has a short residual life, reapplication may be necessary. Follow product label directions for use.
• Bt (Bacillus thuringiensis: This bacterium targets caterpillars by disrupting their digestion. It can be applied to young plants, but it has to be ingested to be effective and will not prevent initial feeding damage.
• Manual removal: Go out in your garden at night with a flashlight to find and remove cutworms. Place them in soapy water or crush them to prevent them from returning to your plants.

Using Bedding Plants in the Landscape

David Hillock, Senior Extension Specialist for Consumer Horticulture and Statewide Master Gardener Coordinator

Bedding plants or annuals continue to be a garden favorite because they provide a full season of color and interest. They also have many uses, to name a few – temporary ground covers, hanging baskets, containers, dried flowers, cutting gardens, wildflower gardens, mass plants, etc. The following tips will help to ensure a successful and stunning display.

Bed Preparation

The key to successful planting is proper bed preparation. Remove all debris and gain control of weeds before planting. Choose a suitable site: i.e. – sun, shade; close to a water source; and away from shallow rooted trees and shrubs, which compete for water and nutrients. Soil tests are recommended to determine proper amounts of fertilizer to apply. Often gardens need only applications of nitrogen. Amend soil by incorporating 3 - 4” of composted organic matter into the area; this improves soil aeration, improves drainage, encourages healthier root systems, and is easier to plant and manage. Spade or till evenly in the organic matter at least 6” deep. After planting, apply a light mulch about 1 inch thick if necessary. Mulches can aid in shading out weed seed as well as moderating soil temperatures and moisture.

Timing

In Oklahoma, planting times will vary depending upon which part of the state you live in. In the north central portion of the state the middle to latter part of April is the time to begin planting many of the annuals available in your garden center or nursery. Southeast residents may be a week earlier, and northwest residents may be about a week later. Remember that these planting times are based on average last frost dates. The planting of warm-season species like Catharanthus roseus (Annual Vinca) should be delayed until warmer weather is sure to stick around, and the soil temperatures are at least 65⁰ F or better.

Design - a Living Bouquet

While the following are not necessarily hard and fast rules and may create a bit of a challenge for some of us, it is certainly worth the time and effort when the right “combination” is achieved. Take time to plan the design properly. Take into consideration cultural requirements, principles of color, and placement of different species. Also, don’t be afraid to copy what others have already proven to be successful.

Avoid planting monocultures (beds with all the same species e.g. – all vinca or all marigold, etc.) or monochromatic gardens (all one color). Instead, try combining several annual species into one design. The benefits of mixing several species together are twofold: 1) it adds interest (height, color, and texture differences) to the garden and is pleasing to the eye. While the flowers and color in themselves are beautiful, using just one flower and/or color will not hold one’s interest for very long. 2) At the same time, you protect yourself from total failure due to a pest particular to one species that could wipe out the whole bed. Mixing species and/or cultivars provides genetic diversity, which reduces the chances of an insect or disease becoming well established in a bed.

Group plants that have the same cultural requirements to increase success; make sure you select those species best suited for the site i.e., sun, shade, wet, or dry (HLA-6425). Do not place plants that thrive in cool, moist shade into a bed in full sun and little water.

Working with colors can be tricky, but by using the following principles and tips, and some practice, you will soon be creating some wonderful bouquets.

• The color wheel is divided into cool and warm hues, using three primary colors – red, yellow, and blue. Cool colors such as blue, green, and violet are subdued. Warm colors such as red, yellow, and orange tend to catch the eye more easily.
• Color groupings can be harmonious or contrasting. Hues are shades of colors. Hues in any neighboring group on the color wheel are harmonious or analogous. Complimentary contrasts are formed by choosing colors opposite each other on the color wheel.
• A successful design will have a balance of analogous and complimentary contrasts.
• White, silver, or gray, and yellow should be used sparingly since they tend to drown out the rest of the design. These colors can be used as a “sparkle” and in general should not make up more than 10 percent of the composition.

In general, flowers need to be planted in drifts or clumps large enough to make a visual difference when viewed from the farthest vanishing point. Of course, this may not be practical as dictated by the pocketbook. But large masses of flowers are more dramatic and satisfying.

Color balancing and strategically placing the dominant colors in the composition or throughout the garden will lead the eye from one end of the bed or garden to the next.

Color balancing can be used to trick the eye into thinking that the garden is deeper or larger than it really is. By using bright strong colors close to the viewer, and then getting progressively bluer and grayer and lighter as you go further back, you can create the illusion of depth.

Height differences can also be used to exaggerate depth by emphasizing the height differential between the little plants in front and the tall ones in the back. The ever-increasing height allows more of each color to be seen enhancing the overall effect.

In general, small, or short plants are placed in the front and tall ones in the back. However, more interest can be created by bringing some of the tall plants closer to the front and pushing short ones toward the back. Some successful combinations for partial or light shade might include begonia, impatiens, wishbone flower and a touch of marigolds for sparkle; for sun you might use combinations of blue salvia, summer snapdragon, vinca, Joseph’s coat, and zinnia and use dusty miller for sparkle.

How Many Bedding Plants Do I Need?

Avoid overbuying or underbuying the number of bedding plants you need. All it takes is some simple arithmetic.

1. Measure the area of your garden and calculate its square footage (width x length = square feet). If the area is irregularly shaped – oval, round or long and winding – a rough estimate is good enough.
2. Use the chart below to estimate the number of plants you will need. You will probably want to get at least a few more than you will need, just in case some are damaged by weather, animals, or pests.

Example: A 125 sq. ft. garden, using plants recommended to be spaced 10 inches apart would need approximately 180 plants.

The above information is only the tip of the iceberg. For more information and ideas look for books that discuss the principles of design and color and study them or visit your local public gardens or retail garden centers for their expertise. Oh, and don’t forget, Have Fun!

Ladybug or Asian Lady Beetles - What's the Difference?

Shelby Mendoza, OSU Student Farm Assistant Manager

This time of year, as we begin working in the garden, we tend to see a lot of what we think are ladybugs. While we are probably seeing some ladybugs, some of the beetles we notice are actually Asian lady beetles. There are more than 400 species of lady beetles in the United States, and most of them are native. However, a few species- like the Asian lady beetle were introduced from other parts of the world.

Asian lady beetles (Harmonia axyridis) are native to eastern Asia and were intentionally introduced into the United States from between the 1960s and1980s. The USDA hoped they would help control agricultural pests in crops such as apples and pecans.

These beetles can range in color from red to orange and look very similar to ladybugs. One common identifying feature of the Asian lady beetle is a black “M” shaped marking behind the head on a white section of their body. Their eggs are small, yellow, and oval-shaped similar to that of ladybugs. Their larvae are shaped like a tiny black and grey alligator with orange or red markings.

If you have found large numbers of “ladybugs” in your house during the fall or winter, chances are they were actually Asian lady beetles. Unlike most native ladybugs, Asian lady beetles commonly gather in large numbers and move indoors to overwinter.

So are they bad in the garden? While Asian lady beetles are not a native species, they can still play a beneficial role. Like many native lady beetles, they feed on common garden pests such as aphids, thrips, spider mites, and scale insects. By feeding on these pests, they can help reduce pest populations in the garden and support natural pest control.