Maryland Grows

Winter is for garden planning

It’s time to plan the 2020 vegetable garden! Or at least time to start thinking about it.


Looking forward to summer harvests

Times have changed – I used to be thrilled when a seed catalog showed up before Christmas, and now it’s “What? The first week of December and only two catalogs have arrived? Don’t they love me anymore?” But I’m sure more will be along soon. Flipping through pages of lavishly-illustrated vegetables and flowers is a great way to spend a winter’s hour or three, but it’s oh so easy to be tempted into buying more seeds than you need. As someone who’s done this multiple times, I’ve developed some strategies for keeping the seed frenzy under control. So, for what it’s worth, here’s my process.

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December Tips and Tasks



  • An amaryllis is a popular holiday gift. With proper care, they can bloom again.
  • Maryland’s Lawn Fertilizer Law prohibits anyone from using fertilizer products to melt ice and snow on steps, sidewalks or driveways.
  • Evergreens like hollies, boxwoods, and pines can be moderately pruned. The trimmings can be used for holiday decorating.
  • To keep poinsettias healthy keep them away from dry, drafty locations. Do not place near heat vents, doorways or drafty windows. Remove the decorative pot cover or make holes in the bottom of it to make sure the water drains from the container when you water.



Please Pass the Cranberry Sauce and Give Thanks for Pollination

Thanksgiving is a time to gather with loved ones and usually involves first preparing and then ingesting a lot of delicious goodies. Each family has recipes and traditions related to Thanksgiving, and even foreigners (like myself) may join in and create new traditions. Independently of who we are and our origin, the meals we prepare include a number of common foods: cranberries, pumpkins, sweet potatoes, pecans, and potatoes.

For this year’s Thanksgiving, I want to take us on a trip to recognize and thank nature and some of our little winged friends, without whom we would not be sharing all that deliciousness with our loved ones. Plus, after reading this you will know some cool fun facts you can share with others during your Thanksgiving meal!

cranberry sauce and the bumble bee that pollinates cranberries

Photos: Wikipedia Commons, Lotherington

Cranberry Sauce

Cranberries are the fruits of a plant closely related to blueberries and huckleberries, which all are native to North America. Like blueberries and huckleberries, cranberries need pollinators to produce fruit. The reproductive organs (anthers – where pollen is produced, and carpels – where the ovules are hosted) in a cranberry flower mature at different times, which means that a flower can’t self-pollinate and needs a pollen vector to produce fruit.

As you may know, no pollination means no fruits, and no fruits means no cranberry sauce. Luckily, nature provides and pollinators are around! We know today that several different bees visit cranberry flowers, with bumblebees being some of the best pollinators. Some other wild bees (for example, mining bees, Andrena) also contribute to the pollination of this plant, and honeybees can pollinate as well but not as efficiently as bumblebees and other native bees.

pumpkin pie and a bee that pollinates pumpkins

Photos: Wikipedia Commons

Pumpkin Pie

Pumpkins, squashes, and zucchini are all closely related vegetables that also require pollinators to produce fruit. Unlike cranberries, pumpkin plants produce separate and distinct female and male flowers. Because in these plants the female and male reproductive organs are physically in different parts of the plant, pollination (and thus fruit production) requires a pollen vector. Again, we would have no pumpkin pie if our pollinator friends were not around!

So, who pollinates pumpkins? Pumpkins have very specialized pollinators that do the best job at pollinating. In the US, this specialized pollinator is the squash bee Peponapis, which feeds their larvae a strict diet of squash pollen. Furthermore, unlike many other bees, both the males and females of the squash bee pollinate, since mating happens in the flower. Even though the squash bees are by far the best pollinators of pumpkins, other bees (including honeybees) can occasionally visit and pollinate the flowers… but really it’s these little cuties that we need to thank for all the delicious pumpkin!

pecan pie and pecan tree flowers

Photos: Wikipedia Commons

Pecan Pie

Like pumpkins, pecan plants can’t automatically self-pollinate and need a pollen vector to produce the yummy nuts we eat. This is not only because their female and male flowers are separated spatially on the plant (like they are for pumpkins); they also flower at different times of the year on the same plant.

To be pollinated, the female flowers of a pecan plant need to receive pollen from the male flowers of another plant which is flowering at the same time. For this reason, pecan flowers need a vector of pollination, which here is not an insect but the wind! Pecan flowers are indeed adapted to wind pollination, displaying hanging bunches that shake with the wind, releasing and catching a lot of the pollen in the air.

sweet potatoes and a bee that pollinates the flowers

Photos: Steven Depolo, Wikipedia Commons

Sweet Potatoes

The part of the sweet potato plant that we eat during Thanksgiving is the tubers, which are roots. And since what we eat is not a fruit, pollinators have no role to play for this Thanksgiving ingredient… at least not directly. But the sweet potato plant still needs pollinators to produce seed and breed, because their flowers are unable to be successfully pollinated by the same flower’s pollen.

Pollinators are then really important for the successful maintenance of the genetic diversity of this plant. Sweet potatoes belong to the morning glory family, and as its name suggests, flower in the morning hours. They are pollinated by many different types of bees (from large bumblebees and carpenter bees to smaller bees such as sweat bees), which visit the flowers for nectar and pollen.

mashed potatoes and a bee that pollinates potato flowers

Photos: Ernesto Andrade,

Mashed Potatoes

As for sweet potatoes, the part of the potato plant we eat is not the fruits but the tubers. Pollinators are not needed for obtaining these tubers, but the plant requires pollinators to be able to breed and maintain genetic diversity. Since they are in the same family (the nightshades), potato flowers look similar to those of tomatoes and eggplants.

Like in those other vegetables, pollinator visits, and more specifically something called ‘buzz pollination,’ needs to occur for successful pollination. In this type of pollination, the insect visits the flower and buzzes loudly, which shakes the flower, releasing the pollen, which they then transfer to a different flower during their next visits. Among these buzzy bees, bumblebees and mining bees (Andrena) are very efficient at pollinating potatoes.

[VIDEO: Buzz pollination of a bumblebee on a potato flower. Note how the pollen is released from the anthers — the four yellow long organs — and sticks to the bee abdomen where the stigma — the female flower organ in the middle of the flower — rubs the bee abdomen where it collects the pollen and gets pollinated. Video by thyreodon.]

Happy Thanksgiving!

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

Featured Video: Ornamental Trimming – Tall Trees

Now is a good time to prune trees. Ray Bosmans demonstrates how to trim tall trees safely and effectively. Make sure to be careful when using a tall ladder.

Take a look at the pruning info on HGIC

Winterizing Figs and Planting Cover Crops in a Changing Climate

Planning, preparation, timing, and flexibility are becoming more important for food gardeners trying to adapt to climate change. For example, some gardeners are planting more late crops and reaping larger and longer harvests of leafy greens in the fall. But severe cold snaps can punctuate long periods of mild weather and injure plants, so being prepared to cover and protect those crops with a floating row cover is still essential.

Similarly, HGIC receives questions each year from gardeners about protecting figs from cold winter weather. If climate change is giving us milder winters do we still need to protect fig plants over the winter? The answer is yes, for most Maryland gardeners, because severe cold snaps will kill aboveground wood even if the average winter temperature is rising. Bending stems as close to horizontal as possible and covering the plant with a tarp or other insulating material is a time-honored technique:

Photo of cinder blocks weighing down fig stems

Two cinder blocks used to weigh down supple one and two year old fig stems. The stems could have been pruned to a more manageable length. Photo credit: Jon Traunfeld


Photo of Bags of leaves around Fig Plant

Fig plant is completely surrounded by bags of insulating leaves.
Photo credit: Jon Traunfeld

Planting cover crops in late summer/early fall is a great way to improve and protect soils. Some vegetable gardeners had tomato, pepper, cucumber and other crops going strong into October and asked us if they could plant cover crop seed past the recommended end date of October 1st. Mild conditions and sufficiently high soil and air temperatures allowed for successful late planting well into October. But if you don’t carefully monitor the 7-10 forecasts you can end up wasting time and money.

This cover crop was sown on November 3rd in Central MD and included winter rye, crimson clover, and hairy vetch. The temperature cooled considerably from the previous week, dropping to a record low of 25⁰ on Nov. 9th:

Photo of soil and seeds

A few hairy vetch sprouts are visible but may be killed by freezing temperatures. It’s unlikely that the crimson clover and annual rye seeds will germinate and survive.
Photo credit: Jon Traunfeld


The availability of tree leaves in fall gives gardeners some flexibility and another option for soil improvement. Leaves can be spread out over the soil to prevent erosion, improve soil health, and provide a nice mulch for next year’s garden plants. Climate change is forcing us to be better planners and to act quickly when dealing with extreme and unstable weather.

Photo of bags of leaves

Tree leaves are valuable for soil and plant health. Don’t let them leave the neighborhood!
Photo credit: Jon Traunfeld

More fig and cover crop information:

By Jon Traunfeld, Extension Specialist

Our Favorite Trees

What are your favorite trees? The Watershed Restoration Specialists from the University of Maryland Extension Sea Grant Program recently shared what their favorite trees are and why.

As Watershed Specialists, we spend a lot of time helping people decide which species of trees might be best for a particular project based on a variety of factors including
sun, soils, and size. Every now and then, people will also see if they can add their favorite tree to the project. Now the number of reasons why people like a particular tree is
probably rivaled by the number of grains of sand on the beach and there’s not enough room in this article to list them all. But this got me to thinking; we spend so much
time talking to other people about trees, I wonder what our favorite ones are? Well, below is the answer to that very question. And after reading this, drop any one of us an email and let us know what your favorite tree is and why.

paw paw tree flowers and fruits

Paw Paw

Amanda – Paw Paw (Asimina triloba)
As an eastern North American native species, not only does Paw Paw have a very distinctive flower, it produces one of the largest edible fruits of all our native trees. The main reason this is Amanda’s choice of favorite native tree is that her son loves the fruit! And because of recent interest in Paw Paw fruit, it has earned the nickname Hipster Banana.

Jackie – Red Maple (Acer rubrum)
Red Maples live up to their name: they give us that first shimmer of red in early spring with its flowers and seeds and wraps up the year with fiery red leaves in the fall. Even
though its nickname is Swamp Maple, Jackie appreciates Red Maples not only for their color, she’s actually made syrup from its sap!

red maple tree and flowers

Red Maple

Kelsey – Willow Oak (Quercus phellos)
A tree she grew up with in her home state of Michigan, Kelsey’s favorite is the Willow Oak. This fast-growing species produces plenty of acorns which keeps the squirrels busy, it also casts a great shadow on her apartment, something she appreciates during the summer months.

willow oak trees and acorn

Willow Oak

Jennifer – Tulip Poplar (Liriodendron tulipifera)
Earning its name from a coffee-cup sized flower that people don’t often see since they’re so high up in the tree, the Tulip Poplar is Jen’s favorite. This tall growing tree is important to a number of birds and butterflies. And its cat-shaped leaf reminds her of the two felines that are really in charge of her house.

tulip poplar tree flower and leaf

Tulip Poplar

Eric – Black Gum (Nyssa sylvatica)
My fave is the Black Gum. I grew to appreciate it over time because of the wide variety of conditions it grows in. And when people tell me they love the red color of a Burning Bush, which can invade natural areas, I often suggest that plants like Black Gum not only have a beautiful red color, they produce flowers and fruit that are beneficial to native insects and animals.

black gum tree red foliage

Black Gum

By Eric Buehl, Senior Agent Associate, Sea Grant Extension Programs. This article was published originally in the Maryland Sea Grant Headwaters Newsletter, October 2019.

November Tips and Tasks

  • Mulch your perennials after the first hard freeze. This helps to protect them from frost heaving caused by the freezing and thawing of the soil. Mulch helps moderate temperature fluctuations, reducing this problem. Mulch should be no more than 2-3″ deep.
  • Be on the lookout for Spotted Lanternfly adults and egg masses. Report any finds to the Maryland Department of Agriculture.
  • Save the time and effort of raking, blowing, and picking up leaves. Leaves are a valuable source of organic matter to improve the soil in a lawn and garden. Leaves that fall onto the lawn can be shredded with a lawnmower and left to decompose naturally in place. Fallen leaves also make an excellent mulch for garden beds. Shred them first by running over them with a mulching mower or a leaf shredder.
Shredded leaves on home lawn

Shredded leaves on home lawn

  • Rosemary topiaries are popular indoor plants. They can be tricky to grow and have trouble adapting to indoor growing conditions. Watch our video for tips.

Refer to the Home and Garden Information Center website for more gardening tips and tasks.