Maryland Grows

How to plant a container-grown tree – Featured Video

Late-winter through mid-spring and early through mid-fall are the best times to plant woody ornamentals, so this is a good time of year to start planning your process if you are interested in adding shrubs or trees to your landscape this year.

Take a look at this video showing you how to plant your container-grown tree, and for more information, view the HGIC page on the planting process.

Salad Tables 2.0

This is a good time of year for cleaning up tools, getting containers ready for starting plants, and maybe even building a Salad Table! The first University of Maryland salad tables were constructed at the Home & Garden Information Center in 2006. The idea for a waist-high raised container garden was based on a row of metal frames on legs I had seen at the edge of a woods at the Accokeek Foundation’s Ecosystem Farm. It was August and the shallow frames were filled with beautiful salad greens. I adapted the design to make it relatively easy and inexpensive to build.

The “University of Maryland Salad Table” carries a State of Maryland trademark for name recognition but was always intended to be an open-source gardening tool. It was popularized in a New York Times article by Anne Raver (a former UME master Gardener!), and by an appearance on the Martha Stewart Show. It has been built and used by gardeners of all ages and circumstances. Videos and building and growing instructions for Salad Tables and Salad Boxes are on the HGIC website. Read More

Q&A: Building Raised Garden Beds With Treated Lumber

raised bed garden
Q: This spring I plan to buy treated lumber to build raised vegetable beds. Please give me a heads-up on treatment options for lumber. I know CCA is out. ACQ is supposed to be somewhat safe. 

Answer: CCA-treated wood (containing copper, chromium, and arsenic) is no longer available for residential use as of 2004. The relatively new chemical treatment ACQ (alkaline copper quaternary) is safe to use in food gardens. Some of the copper may leach over time from the lumber, but the risk to human health is considered to be low. From research we have seen, a toxic level of copper would kill the plants before the edible fruit, roots, or plants would be harvested. If you have doubts, select a different material such as brick, stone, and untreated or plastic lumber. You can forego any enclosure by mounding soil 4-6 inches above grade, leveling the top and sloping the sides.

Refer to the Home and Garden Information Center website for more information on Materials for Building Raised Beds. For further details about wood preservatives, refer to the National Pesticide Information Center’s web page, Home and Garden Use of Treated Wood.

By Ellen Nibali, Horticulturist, University of Maryland Extension Home and Garden Information Center. Ellen writes the Garden Q&A for The Baltimore Sun.

Have a plant or insect question? University of Maryland Extension’s experts have answers! Send your questions and photos to Ask an Expert.

Gardening Resolutions 2020

Happy New Year! At the beginning of January we typically think through what we plan to do better in the coming twelve months in all aspects of our lives, whether that’s reading more books or committing to a fitness program or eating healthy. Of course we don’t always follow through, but it’s still worth considering what might make our lives better–including our gardening lives! Here’s just a snippet of what I’m focusing on in 2020. Read More

January Tips and Tasks

Snow covered shrub

  • Heavy snow and ice loads can damage shrubs. Using an upward motion, gently sweep snow loads off of shrubs to prevent breakage. But oftentimes bent or weighed down branches will spring back after the snow/ice melts.
  • Problem tree branches (hanging very low or storm damaged), may be removed as needed. It is not necessary to wait until spring for this type of pruning.
  • Cut back or stop fertilizing houseplants unless they are grown under supplemental lighting.


  • Avoid the temptation to start seeds too early. Check seed packets for detailed information on starting various types of flowers. Do not depend on window sill light to grow these seedlings. Refer to our instructions on starting seeds indoors.
  • Don’t store firewood inside your home. Only bring in enough to burn at one time. Bark and other wood boring beetles may emerge inside the home.
  • Be on the lookout for spotted lanternfly egg masses on the trunks of trees.
Spotted lanternfly egg mass

Spotted lanternfly egg mass
Photo: Emelie Swackhamer, Penn State University,

Serpentine Soils Are Anything But Barren: They Support a Unique Grassland Habitat

I have never been to the African grasslands, where lions, zebras, elephants, and wildebeests seem to be in continuous danger. I have, however, been to a Maryland habitat that few people know about, and that, even though lion-, zebra-, elephant- and wildebeest-less, reminded me strongly of those African savannas.

This habitat I am talking about is the Serpentine Grasslands (or Barrens) of the Eastern United States. If you have never heard of them, fear not! Hopefully, by the end of today’s post, you will know a bit more about them and you’ll even try to go visit the few remains that still exist of this beautiful but endangered habitat of our region.

Serpentine Barren Grassland

Fig. 1 – The Serpentine Grasslands of Maryland at Soldiers Delight. Photo: U. Weber.

As you may have guessed from its name, Serpentine Grasslands or Barrens are prairies where the dominant plants are grasses. This is all good, but if they are grasslands, why are they also called Barrens, you may be asking yourself. The answer to that question is what in my opinion makes these habitats so fascinating; something that is also hidden in the other part of their name: “Serpentine”. Indeed, the word Serpentine refers to the type of soil these grasslands are on.

Serpentine soils form on a type of bedrock called serpentinite. This type of rock only exists in places where tectonic plates come into contact, fold, and volcanic activity occurs. This happened in our area about 480 million years ago when the Appalachian Mountains formed. Because of this, there is now an arc of serpentinite present in the Maryland-Pennsylvania area, parallel to the mountains.

Serpentine Soil

Fig. 2 – The Serpentine Grasslands have usually bare soils that have a greenish tint, due to the serpentinite they originate from. Photo: A. Espíndola.

Serpentinites are rich in many metals and other compounds that make the soils that form on top of them relatively toxic and unfriendly to many plants. Because not many plants can grow on these soils, not much soil is retained and the ground ends up being rocky. Because of this characteristic, places with these soils are not very fertile, and, when the Europeans arrived in the area, they started referring to them as ‘barren’, since they were not only infertile, they also had no timber on them. However, even though they were referred to as barrens, many plants do grow on these thin soils, and actually, many of Maryland’s rare flower plants and grasses are adapted to grow in this habitat!

Indeed, the Serpentine Grasslands of Maryland and Pennsylvania are some of the unique places where it is possible to find, for example, the rare moss pink, serpentine aster, or the sandplain gerardia (Fig. 3). It is also home to several endangered and rare species of butterflies and moths such as the Dusted or the Cobweb Skipper (Fig. 4).

Even though the plants and butterflies present in this habitat are relatively well-studied, we still know very little about what other organisms live in the grasslands. To remediate this, in my lab at the University of Maryland in College Park, we are working on trying to understand better what species of insects are present in the area.

Plants of the Serpentine Barron

Fig. 3 – Many rare plants are present in the Serpentine Grasslands of the Eastern US. For example, the moss pink (left; Photo: J. Gallagher) and the sandplain gerardia (right; Photo: A. Espíndola).

For the moment, we are focusing on insect pollinators, and our first works indicate that the plants growing in these grasslands are pollinated not only by bees but also by hoverflies, showing how important these lesser-known pollinators may be to sustaining a very rare habitat of our region. (Take a look here to learn more about hoverflies as pollinators.

The Serpentine Grasslands had not always been rare and endangered. Indeed, serpentine soils extended for quite an area in the Maryland-Pennsylvania region. So, what happened to this habitat that made it so rare today? Ecologists and historians can help us with this.

Like many habitats dominated by grasses, Serpentine Grasslands need fire to sustain themselves. In the absence of fire, pines and red cedars from the surrounding areas start establishing in the grasslands and compete with the grasses and all the rare plants, making the once grassland become an encroached pine forest. When the Europeans first arrived in our region, documents said that there were Serpentine Grasslands that extended for at least 130,000 acres. Today, Serpentine Grasslands occupy about 1.6% of that area.

These grasslands were managed as hunting grounds by several tribes (Susquehannock, Shawnees, Lenape Delaware), who burned them regularly to maintain the grasses and attract large herbivores to hunt. These tribes had complex systems of rights over these lands, which they shared with neighboring tribes as needed. Records show that these extensive grasslands were extremely rich in fauna. There were a myriad of birds (mentioned in some records to ‘have darkened the sky’ when migrating!), wolves, bears, cougars, deer, and buffalo roaming these regions!

European colonizers quickly realized that these grasslands were great land for cattle and hunting, and thus started settling and claiming the native tribes’ lands. However, the new inhabitants did not continue the practice of burning, which led to the habitat starting to degrade and finally becoming less appropriate for cattle and cropping.

Eventually, these lands were relegated as ‘useless’ lands and were thus prime land for building or just reinvaded by pines and other trees, which were used for timber. I sometimes try to imagine what these lands — today just 30 minutes away from my house — may have looked like with those large fascinating animals living right here.

Dusted Skipper

Fig. 4 – The Serpentine Barrens are the habitat for several rare moth and butterfly species, such as the Dusted Skipper (Photo: A. Wells).

Today, the Serpentine Barrens are protected and managed with fire in several parts of the state. A large part of these protected lands are not open to the public. However, we are lucky that some places are indeed accessible to the public and can be visited throughout the year.

The largest remnant of Serpentine Grasslands on the Eastern Coast of the US is west of Baltimore, in the Soldiers Delight Natural Environment Area. Another public land where some remains of Serpentine Grasslands are still visible is in Northern Baltimore, at Lake Roland Park.

I am lucky enough that I can visit and work in these fascinating places. If you have never been to them and would like to see these local jewels, take me up on the invitation and consider hiking some of their trails. The spring and summer are gorgeous on these lands, and who knows, you may be lucky enough to see one of those rare beauties that still live there!

By Anahí Espíndola, Assistant Professor, Department of Entomology, University of Maryland, College Park

Seeds and Seed Catalog Jargon

Seed catalogs arrive this time of year with appealing photos of vegetable crops that buoy our hopes for a bountiful garden. The sheer number of vegetable, flower, and herb offerings is breathtaking, with seed companies offering 20 to 40 new cultivars each year. These may be brand-new releases or just new for a particular company. I recently scanned a few catalogs and discovered ‘Home Run’ melon, ‘Naval’ carrot, ‘Double Take’ columbine, ‘Rouxai’ leaf lettuce, and ‘Green Machine’ zucchini.

Seed catalogs

Companies often tout All-American Selection (AAS) Winners, cultivars evaluated and selected by a well-known independent, non-profit organization. Some of the small seed companies carry seeds from the

Open Source Seed Initiative (OSSI), a group of breeders and seed companies committed to open-source breeding.

There are dozens of wonderful seed companies and organizations that are a click away. But please also consider supporting local businesses and farmer co-ops with your seed and transplant purchases.

Seed Swaps

Seed swaps offer another great way to get and share seeds. These events are fun, educational, and interactive. National Seed Swap Day is January 25, 2020: (information not yet updated for 2020). Several UME Master Gardener programs (e.g., Carroll Co., Calvert Co., Anne Arunel Co.) are holding scheduled seed swap events in January, 2020.

Seed and Cultivar Terms Frequently Encountered in Seed Catalogs

Cultivar– a cultivated variety of a specific crop. Example: ‘Red Ace’ is a beet cultivar. Cultivar is a contraction of “cultivated” and “variety” and is often used synonymously with “variety.”

Open-Pollinated– an in-bred variety where individual plants in a population cross-pollinate each other and produce nearly identical offspring. When grown using appropriate precautions, these varieties “come true” when seed is saved year-to-year.

Hybrid- controlled cross-breeding of two distinct, inbred, open-pollinated cultivars. The seed harvested from the intentional cross will produce an F1 (first filial) hybrid. Hybrids tend to be vigorous, uniform, and productive, and many have some disease resistance. Producing hybrid seed is labor-intensive, accounting in part for the often higher price. Hybrid seed is not true to type: seed saved from this year’s crop and planted next year will not be uniform in appearance or identical to the mother plants. Therefore, hybrid seed must be purchased each year.

Heirloom– open-pollinated cultivars that persist because their seed is saved and passed down from one generation to the next. They contain valuable germplasm that would be lost without the efforts of individual gardeners, farmers, small seed companies, seed-saving groups, and the USDA. They often have a colorful history and add interest to the garden and dinner table. Heirloom cultivars vary widely in productivity and disease and insect resistance.

Treated Seed– may be coated with a chemical fungicide (usually pink or purple in color) to prevent injury from soil-dwelling diseases after seeds are planted. The most common crops treated are corn, pea, and bean. Another treatment is immersing seeds in hot water to kill pathogens on, and inside of, seeds.

Untreated Seed- seeds that are not chemically treated.

Organic Seed- harvested from crops that are grown and certified according to the USDA National Organic Program (NOP) guidelines. To be certified “organic” seed must be produced and handled by certified organic producers. The NOP requires organic farmers to plant organic seed unless it is not commercially available. You can grow vegetables organically at home using non-organic, untreated seeds. Related resource: Organic Seed Alliance (national education, research and advocacy organization.)

Disease Resistant – ability to resist or impede a disease-causing pathogen. The level of resistance may be high or intermediate. This can also apply to insect injury. For example, sweet corn cultivars with long, tight ear leaves resist corn earworm feeding. Cornell University has excellent charts for identifying and selecting disease-resistant cultivars.

Disease Tolerant– ability of a cultivar to tolerate a disease infection or adverse environmental condition (e.g., drought, cold temperature) without a significant reduction in growth or yield.

Indeterminate / Determinate– the shoots of indeterminate tomato cultivars continue to grow and branch throughout the growing season. The shoots of determinate type cultivars reach a certain length and terminate in a flower cluster. Determinate tomato cultivars range in height from less than 1 ft. to 5 ft. and are sometimes referred to as “self-topping.”

Days to Maturity (Days to Harvest)- the approximate number of days to harvest, either from planting seeds or transplants. For tomato, pepper, eggplant, muskmelon, watermelon, broccoli, cabbage, cauliflower, and Brussels sprouts it’s usually days from transplanting, and for all other annual crops it’s days from direct seeding.

Parthenocarpic- flowers are able to set fruit without pollination and fertilization (of ovule by sperm cell). ‘Tasty Jade’ and ‘Diva’ are cucumber examples. ‘Cavili’, ‘Partenon,’ ‘Dunja,’ and ‘Golden Glory’ are summer squash examples. Growing a seeded cultivar nearby will lead to seeds forming in the parthenocarpic cultivar.

I learned that one of my favorite zucchini cultivars, ‘Costata Romanesco’ is largely parthenocarpic. A Cornell University study reported that 58% of bagged female flowers set marketable fruits.

Gynoecious- flowers are predominately female, leading to more fruits per plant. Unlike parthenocarpic cultivars, gynecious cultivars require pollination. Some companies include a second cultivar to plant that has both male and female flowers (monecious). Otherwise, you’ll need to buy and plant a second variety. Expensive cultivars (e.g. ‘Socrates,’’Tyria’) are available that are both gynecious and parthenocarpic. Seeds cost more because of specialized breeding and increased yield potential.

Pelleted– small seeds (carrot, lettuce, onion) are surrounded by a clay pellet to make handling and planting easier.

Primed– pelleted seeds may also be “primed” to reduce germination time. Seeds receive enough water to almost germinate, and are then dried and stored. These primed seeds break dormancy and germinate quickly when planted. The process also shortens the seed’s storage life.

Bolting (going to seed)- flowering prematurely, usually due to unsuitable climatic conditions at certain stages of growth. Spinach, lettuce, cilantro, broccoli, and endive are crop species prone to bolting.


Do you have a few favorite cultivars you’d like to share with us?

The HGIC fact sheet Recommended Vegetable Cultivars for Maryland Home Gardens needs to be updated. We would love to know which vegetable cultivars you would recommend to your fellow gardeners. Please send a list of your favorite cultivars to with a few words or a few sentences about why you like them (e.g., high yields, dependable, early maturing, heat tolerant, disease resistant, etc.)

By Jon Traunfeld, Extension Specialist