Category Archives: Horticulture

From The Henrico Extension MG Help Desk: Oak Galls


Photo credit: Lynn Holterman, used with permission

I have an oak tree that has a weird looking fruit on it.  Can you help identify it?


Thanks for the pictures.  What you see in the picture on the oak tree is a gall caused by a non-sting wasp.  It is common among oaks to develop galls at this time of the year.  Galls can vary in shape and size.

Galls are usually only cosmetic problems on the oaks.  We do not have any treatment options for them.  Once you see the gall, the insect is already inside the gall.  So if there was a treatment, it wouldn’t get rid of the gall.  If you want you can cut out the galls (again, non-stinging wasp, so no concern of getting stung).  But I would just leave them.  Usually we see galls for a couple of years on a tree, then we won’t see them again for many years, if at all, as part of natures cycles.


Galls are abnormal growths of plant tissue induced by insects and other organisms. Gall-making parasites release growth-regulating chemicals as they feed, causing adjacent plant tissues to form a gall. The parasite then develops within the relative security of the gall.


All resource links accessed May 8, 2018


Lynn Holterman, used with permission

Do you have a gardening question that the Henrico Master Gardener Volunteers can help you with?  The Henrico Extension Master Gardener Horticulture Helpline provides expert advice and guidance on a variety of gardening topics.

The Henrico Master Gardener Horticulture Helpline can be reached at (804) 501-5160, which also serves as the main number for the Extension office. The helpline will be staffed from 12:30 to 4:30 p.m. Mondays and Fridays and from 9 a.m. to noon Tuesdays, Wednesdays and Thursdays through October.

In addition, the public may call from 8 a.m. to 4:30 p.m. weekdays to leave a message. A Master Gardener will respond during the next shift.

For the helpline, a team of volunteer Master Gardeners will have access to a vast library of Extension publications and information on horticulture topics. Henrico’s Master Gardener program provides education and promotes research-based information on horticulture to the gardening public. For more information, go to

Answers provided herein were based on specific situations and growing conditions.These recommendations may or may not be appropriate for all circumstances.For specific recommendations for your particular situation please contact your local Cooperative Extension Office.

International Compost Awareness Week

May 5-11, 2019 is International Compost Awareness Week!
Compost is produced when organic matter, such as garden and lawn waste, is broken down by bacteria and fungi. When added to soil it improves soil structure; sandy soils will hold water better while clays will drain faster. Compost also promotes a biologically healthy soil by providing food for earthworms, soil insects, and beneficial microorganisms.
Learn more about composting with these Virginia Cooperative Extension Publications:
If you have any questions about composting, Contact the Henrico Master Gardener Horticulture Helpline at 804.501.5160.

You may sign up for the Henrico County Extension Agriculture email distribution list by using the following link:

Learn how to become a Henrico Master Gardener: .  Applications will be available for download September 1.

Keeping Your Lawn Healthy This Winter, part 3

The fescue and/or bluegrass lawn that is so prevalent in Henrico is reliably winter hardy. However, while well adapted to winter, these cool season turf varieties may be injured in cold weather. There are a number of things that you can do and also not do to minimize the risk of winter turf damage.


Snow Molds: Snow molds are not nearly as big of a problem in Virginia lawns as they are further north. However, when they occur, they certainly attract a lot of attention. Following winters with extended snowfall, it is possible that cool-season lawn grasses have been attacked by either pink or gray snow mold. The blighted turf will be a circular patch of varying size of matted down turf. The diseases are more likely to occur on succulent turfgrass leaves that received very high levels of fall Nitrogen fertilization; so again, proper fall fertilizer is key. It is not generally recommended that home lawns be treated for snow molds because the disease is rarely going to kill turf in this setting. Use a heavy garden rake to work up the matted turf in the affected areas in order to increase air and moisture movement into the turf canopy. Observe the area over the next 7 days or so to see if new shoots are emerging from the crowns. If you don’t see any signs of new growth after that time period, then plan on reseeding these areas.

Red Thread or Pink Patch: Spring-like temperatures and plenty of moisture result in ideal conditions for turfgrass diseases to make an appearance in lawns, particularly cool-season grasses. The disease present is likely one of two things: Red thread or Pink patch. The bright red to pink mycelial growth of this fungus is plainly visible early in the morning, particularly when the dew is still on the grass. The disease will remain an eyesore as long as cool, moist periods persist, but the fungus only attacks the foliage and rarely will the entire plant die. What should you do to manage this disease? Almost always, the proper treatment is to leave it alone rather than applying a fungicide. As the weather warms and dries, red thread and pink patch will gradually disappear.

Part 1 of this series can be found here.

Part 2 of this series can be found here.

National Invasive Species Awareness Week February 26 – March 2, 2018

While the term “invasive plants, pests and diseases” may not be familiar to everyone, the effects of invasive species in Henrico County should be of concern to all of us. Once invasive pests become established, they can grow and spread rapidly, often because they have no natural predators in their new environment. Invasive pests cost landowners, industry and the U.S. government millions of dollars to control, so taking steps to prevent their introduction is the most effective method of reducing both the risk of invasive species infestations and the cost to control and mitigate those infestations.

Henrico residents can help reduce the spread of invasive pests and plants into the county and the Commonwealth by following these simple steps:

1. Learn about invasive species, especially those found in our region. Invasive species such as the Asian longhorned beetle, emerald ash borer, gypsy moth and imported fire ant wreak havoc on the environment and also displace or destroy native plants and insects.

2. Clean hiking boots, waders, boats and trailers, off-road vehicles and other gear to stop invasive species from hitching a ride to a new location. Learn more at

  1. Avoid dumping aquariums or live bait into waterways.
  2. Don’t move firewood – instead, buy it where you’ll burn it, or gather on site when permitted.  Gypsy moth egg cases and emerald ash borer larvae can hitch a ride with the firewood and start infestations in new areas. Learn more at
  1. Use  forage, hay, mulch and soil that are certified as “weedfree.”
  2. Consult with your local nursery or master gardener to help you select plants that are not invasive for your landscaping and gardening projects, and remove any known invaders.
  3. Volunteer to help remove invasive species from public lands and natural areas.

Keeping Your Lawn Healthy This Winter, part 2

The fescue and/or bluegrass lawn that is so prevalent in Henrico is reliably winter hardy. However, while well adapted to winter, these cool season turf varieties may be injured in cold weather. There are a number of things that you can do and also not do to minimize the risk of winter turf damage.


Winter Weed Control: Maintaining a vigorous turfgrass stand will protect against weed infestation. However, during the winter months turfgrasses are not actively growing and are, therefore, susceptible to the encroachment of winter annual broadleaf weeds. Winter annuals germinate in the late summer and early fall months, live during the winter and die in the latespring or early summer with the onset of high temperatures. Examples include annual bluegrass, common chickweed, purple deadnettle and henbit.

Controlling winter annual broadleaf weeds before they are able to set seed will not only reduce the likelihood of an outbreak the following year, but improve the aesthetic quality of the turfgrass stand.

Control of winter annuals includes removing plants now by hoeing or hand pulling. Broadleaf herbicides can also be effective if used while the weed is actively growing or before the weed flowers in spring. Realize herbicides are not effective at cold temperatures. Generally postemergence herbicides are used when temperatures are > 50o F. Be sure to read and follow all label directions.

Voles: Voles will make runways under lasting snow cover in lawns as they feed on grass blades and roots and are protected from predators. Damage is frequently mistaken as mole damage, but moles are not active during winter and actually tunnel below the soil surface. Vole damage appears as runways or winding trails of damaged grass. Lawns usually fill-in as conditions warm in spring. A winter without lasting snow is an excellent avenue of free vole control, as vole activity on exposed lawn areas will be greatly reduced without the protection provided by the snow.

Part 1 of this series can be found here.

Keeping Your Lawn Healthy This Winter, part 1

The fescue and/or bluegrass lawn that is so prevalent in Henrico is reliably winter hardy. However, while well adapted to winter, these cool season turf varieties may be injured in cold weather. There are a number of things that you can do and also not do to minimize the risk of winter turf damage.


Proper Fall Fertilizer: Did you fertilize correctly in the fall? In Henrico, the last date to apply fertilizer is the end of November. Fertilization during the winter period leads to higher potential leaching and runoff risk of the nutrients.

Final Cut: The final cut of the season should be on the lower recommendation for height for fescue or bluegrass. That would make your final cut of the year at 3” height. This keeps your grass from getting too tall and having those tall blades that flop over on itself which can promote diseases. After your final mowing, put you lawn mower to rest for the winter by having the blade sharpened and performing a tune-up.

Stay off Frozen Turf: Trafficking on frost or ice-covered turf usually results in extensive physical “breaking” of the leaves. The xylem and phloem tissues that are involved in moving water, nutrients, and carbohydrates around in the plant are usually severed when traffic is applied to ice-covered foliage. The damaged turf leaf blades don’t fall away completely from the stem, but instead slowly turn brown and die. So follow the practice of golf courses and stay off frost covered or frozen turf. It is OK to go on turf covered by snow. The snow will help cushion and protect the blade from damage as well as protect it from extreme cold.

Stay off Overly Saturated Turf: Winter rains or melting snow can make your lawn saturated with water. When this happens, stay off the turf to avoid compaction. Remember that you just aerated the lawn in the fall to improve compaction in the lawn; do not undo that work now by walking over overly saturated turf.

Be Careful with Ice Melt Materials: Standard ice melt compounds are usually some form (or combination of) chloride-based salts. Limited use of any of these products should cause little injury. Problems begin when they are used excessively and there is not adequate rainfall to wash or leach the material from the area. We are often prone to over applying ice melt just to make sure the ice and snow melts. Keep in mind this can damage concrete surfaces as well as the plants and grass growing along the walks and driveways. If problems develop, they are normally latent and do not show up until spring or summer

World Soils Day, December 5, 2017

World Soil Day (WSD) is held annually on December 5th as a means to focus attention on the importance of healthy soil and advocating for the sustainable management of soil resources.   An international day to celebrate Soil was recommended by the International Union of Soil Sciences (IUSS) in 2002.

A soil test can provide information on the proper amount of lime and fertilizer to apply to your lawn, garden and other areas of your landscape.  When gardeners apply only as much lime and fertilizer as is necessary and at the appropriate time, nutrient runoff into surface or ground water is minimized, money is saved, and plant health is optimized. Soil testing can also be used to diagnose common nutrient deficiencies for plants that are growing poorly.  Virginia Cooperative Extension recommends that the soil be tested every three years.

More than a third of garden samples tested by the Virginia Tech Soil Lab have too much lime, creating an alkaline soil that can cause micro-nutrient deficiencies in plants, yet many gardeners blindly add lime to their garden and lawn yearly.

So Don’t Guess, Soil Test!

Soil testing is easy and simple.  It can be done anytime the soil is workable.  Kits are free, however, there is a fee for processing the test and postage to mail to the soil lab at Virginia Tech.  In order to promote the practice of soil testing, the Henricopolis Soil and Water Conservation District has established a soil test incentive program to offset the cost of soil analysis for Henrico County residents. Henricopolis will provide up to 2 coupons per household to cover the $10.00 processing fee for a standard soil test (not including postage).  People wishing to participate in this incentive program must request a soil test voucher. Vouchers are available by email or in-person at the Henricopolis SWCD office.  Emails must include your name, physical address, and number of vouchers requested (maximum of 2 per household).  Email requests to

Soil Test kits may be obtained from the Henrico Extension Office or at your local Henrico Library.


Plant Profile: Lycoris

 Carlton Hines, 2017 Henrico Master Gardener Intern

Lycoris is a flowering plant and perennial herb from the Amaryllis family. It is known commonly as the resurrection lily, surprise lily, spider lily, and/or hurricane lily. It grows by bulb, and never bears leaves and flowers at the same time. Its leaves are strap or lance-shaped, its flowers contain three to six petals, and their fruits are either in the form of fleshy berries or dry capsules.

Photo Credit: By Blue Lotus – Flickr, CC BY 2.0,

Blue-green foliage grows in the fall through spring from a bulb, then dies back to the ground without a single bloom. After “taking much of the summer off” they suddenly erupt with growth. Within a 5-day period, they reach heights of 18 inches, boasting circular clusters of 2-inch-long flowers. The backward curving sepals and petals, combined with long, upwardly arcing pistols and stamens, resemble a spider. The flowers bloom for several weeks, coinciding with hurricane season. Only two species of Lycoris are readily available in the United States, which are Lycoris radiata and Lycoris squamigera.

Lycoris radiata are the least winter hardy species, growing in USDA Plant Hardiness zones 6-10. Bulbs require 9” spacing with the top ¼” exposed. They grow 12”-18” tall with an equal spread. Red, non-fragrant, showy flowers bloom between August and September in full sun to part shade with medium water requirements and medium maintenance. Flowers will prefer some shade in warmer climates. The naked flower scapes bear an umbel and 4-6 light coral red flowers. Leaves appear in fall, overwintering and lasting through spring. L. radiata are not prone to pest and insect damage.

Lycoris squamigera are more cold hardy, growing in USDA Plant Hardiness zones 5-9. Bulbs should be planted 5”-6” deep and spaced 6” apart. They grow 12”-18” tall with an equal spread. The naked flower scapes begin their growth in late summer to bear 4-7 funnel-shaped flowers that are fragrant and rose pink in color. Flowers bloom August to September in full sun or part shade with medium water requirements and low maintenance. L. squamigera is called the “magic lily” and is found typically in shady woodlands. Plants are not prone to pest and insect damage.

Photo Credit: By Namazu-tron (Self Shot) [GFDL ( or CC BY-SA 3.0 (], via Wikimedia Commons

Bulbs are best grown in organically rich soil in a sheltered location. They are effectively planted in open woodland gardens or meadows, with annuals, perennials, and groundcovers. They should be mulched in winter. The bulbs are very durable, tolerating poor soil and dry or overly waterlogged conditions. They may take a few seasons to establish, but over time will naturalize by bulb-offsets.

In warmer regions, growth begins in fall, enduring through spring. In colder regions leaf growth starts in spring. Leaves die back without too much of a mess, leaving a nitrogen-rich food source for its bulb. Harsh winters may diminish flower hardiness, which can prevent them from flowering the following summer. If growing in pots, bulbs require a large growing space with potential for deep root development. Containers that are too small will cause “failure to thrive” syndrome and not flower at all.

Quick Blog Post – Easter Lilies

Easter Lilies are a tough crop for a greenhouse grower.  Why are they a tough crop?  Because the Monday after Easter, they aren’t worth anything!  Timing is very critical on Easter Lilies.  You really only have a 1 week window where you can sell them.

lilyHere is a great article on Easter Lilies from Texas A&M.  In addition to some great history and other information about the lily, it provides great planting instructions so you can enjoy it for years and years as a perennial in your garden.