Coverdale Farm

Ian Stewart & Lori Athey

Now that spring is here many Delawareans are enjoying the colorful wildflowers blooming in their backyard, local parks and road sides. Unfortunately, the great majority of those currently flowering are alien weeds which were either deliberately or accidentally introduced by Europeans. These plants found themselves in a new environment with few or no natural enemies and spread rapidly across our area. Each weed produces hundreds if not thousands of seeds and an entire backyard can be riddled with them in just a few years.

The three most common yellow-flowered weeds have been covered in a previous blog (http://blog.delawarenaturesociety.org/2015/05/06/the-not-so-mellow-yellows/) and this follow-up blog highlights some of the other visually-appealing wildflowers that people may not realize are aggressively invasive aliens.

Three common backyard weeds stay low but spread rapidly to form sun-blocking carpets that inhibit or prevent the growth of any native seeds beneath them. Speedwell (Veronica sp.) is one of the first wildflowers to emerge and its four-petaled circular blue flower can be seen as early as March. There are several species of speedwell but most are alien. Ground ivy (Glechoma hederacea) produces dozens of tiny purple flowers and spreads by underground rhizomes which makes it especially difficult to control since pulling one part of the plant will not suffice. Clover (Trifolium sp.) is particularly common in farm fields, perhaps because it may have been introduced as livestock feed, but is now ubiquitous in urban and suburban settings. Clovers have three leaves, each with a distinctive white chevron, though finding one with four leaves may bring you luck! There are two sister species, the red and white clover, which are named after the color of their flower.

Speedwell (Left) and Clover (Right)

Ground ivy

Two striking members of the Mint family also stay quite low to the ground but are easily seen because they often grow in large patches. Purple deadnettle (Lamium purpureum) and henbit (L. amplexicaule, also known as clasping deadnettle) often grow together in fields and backyard although the former is much more common.

purple deadnettle

Henbit

Finally, three conspicuous white-flowered members of the Mustard family are widespread throughout the Piedmont. Garlic mustard (Alliaria petiolate) and roadside penny-cress (Thlaspi alliaceum) are both knee-high single-stemmed weeds which form large clumps in sunny areas, while hairy bittercress (Cardamine hirsute) is quite a bit smaller and branches into multiple small flowers.

Garlic mustard

roadside penny-cress

Penny-cress up close

Purple deadnettle (on left) and hairy bittercress (on right)

These alien wildflowers are especially problematic because they bloom in early spring and may have already produced seeds before householders begin mowing. Although it is an uphill battle, most weeds can be controlled by hand-pulling them before they go to seed, especially if the whole root system is removed.  Repeated early mowing or weed-whacking will deplete the weeds’ resources before they even flower. If you have a large yard or field an alternative option is to gradually convert it into a meadow with long grass and native wildflowers which is left standing throughout the winter and early spring. This helps to restrict early-growing weeds like ground ivy and deadnettle by reducing the amount of sunlight they receive.

Once you have removed the alien weeds you can replace them with native wildflowers which are much better for wildlife, especially our declining pollinator insects as well as the animals that feed on them. A perfect opportunity is the Delaware Nature Society’s Native Plant Sale which is held at Coverdale Farm in Greenville. It starts with a member’s-only day on Thursday May 2nd (1pm-7pm; though you are welcome to attend and join in person) and is then open to the public Friday May 3rd (3pm-7pm) and Saturday May 4th (9am – 3pm). Admission is free and there will be plenty of staff and volunteers present to answer any questions about plants and help you load them into your car!

The full catalog is online here but just to whet your appetite, here is a selection of groundcover plants which are tough and fast-growing and have a decent chance at outcompeting those pesky weeds!

Dry sunny location

Andropogon virginicus (Broom Sedge) grass

Coreopsis verticillata (Whorled Tickseed) perennial

Geum fragarioides (Barren Strawberry) evergreen perennial

Phlox subulata (Moss Phlox) evergreen perennial

 

Dry shaded location

Antennaria plantaginifolia (Woman’s Tobacco Pussytoes) semi-evergreen perennial

Chasmanthium latifolium (Wild Oats) grass

Geranium maculatum (Wild Geranium) perennial

Polystichum acrostichoides (Christmas Fern) evergreen fern

 

Moist shaded location

Asarum canadense (Wild Ginger) perennial

Osmundastrum cinnamomeum (Cinnamon Fern) fern

Phlox stolonifera (Creeping Phlox) perennial

Zizia aurea (Golden Alexanders) perennial

 

Moist to wet sunny location

Carex cherokeensis (Cherokee Sedge) grass

Eupatorium perfoliatum (Boneset) perennial

Iris versicolor (Blue Flag) perennial

Panicum virgatum (Switchgrass) grass

 

Ian Stewart

Happy New Year everyone! If you’re looking for an interesting New Year’s Resolution to get you outdoors, why not seek out and learn about a different tree every month? This is exactly the time of year to spot one of Delaware’s most distinctive trees – the Osage orange.

The Osage orange (Maclura pomifera) is a small to medium-sized deciduous tree native to the Midwest that was originally restricted to a relatively small stretch of Arkansas, Oklahoma and Texas. It is not related to oranges but is in the Mulberry family. The name refers to the bright orange color of its wood and the Osage Nation, a midwestern Native American tribe who used the wood for making bows and apparently supplied early settlers with young plants.

The exposed orange roots of a fallen Osage

Although their original range was small, Osage oranges are now found throughout the lower 48 states after lines of them were planted to provide windbreaks in flat open landscapes such as farmland and isolated homesteads. Lines of Osages were also planted throughout the rest of the country to act as natural thorny fencerows for housing livestock and to delineate driveways and land borders, which is why you most often find Delaware Osages arranged in rows on either side of old country roads. Coverdale Farm Preserve’s famous ‘Avenue of the Osages’ contains no fewer than 72 of these striking trees which were probably planted over a hundred years ago.

Coverdale Farm’s famous ‘Avenue of the Osages’, with fallen fruit in foreground

Gnarly, orange-tinged bark of an Osage

The easiest time of year to identify Osage oranges is in the middle of winter as the bare trees now reveal their distinctive gnarled orange-tinged bark made up of many twisted strips. Some trees still bear their large green fruit, commonly known as ‘monkey brains’, although most of these have now fallen to the ground. Be careful – if they fall on a sidewalk or road they become a slippery hazard to pedestrians and motorists alike!

Osage orange fruit with knobbled surface

Interior of an Osage fruit with some seeds

Osages occur as either male or female trees but only the female trees produce the softball-sized fruit which contains several small seeds within its gooey white flesh. Although the fruit is edible almost all animals ignore it as it is tough, unpalatable and exudes latex, so the clusters of monkey brains simply remain where they fall until they decay. Squirrels do eat the seeds however, which may be why you see so few young trees mixed in with the old ones.

Interestingly, almost every Osage I see has a poison ivy vine growing up its trunk, perhaps because the vine finds it easy to grip onto the furrowed bark. Next time you are a passenger in a car being driven along a country lane, try to spot some rows of Osage oranges. If you spot some it might make you resolve to learn about our local trees in 2019!

This Osage was cut down at Coverdale and has about 90 growth rings, suggesting it was at least 90 years old. The poison ivy vine seen in cross-section on the left of the trunk had 19 growth rings so it had been attached for many years.

By Ian Stewart

The buzz around this year’s Native Plant Sale is building to fever pitch! Our plant sale comes at the perfect time as we have finally emerged from the frigid gloom of an unusually long cold winter to find colorful wildflowers emerging all across the state. These ‘spring ephemerals’ are so-named because they only flower for a fairly short time since they start losing the sunlight once the trees leaf out.

We are fortunate to have a lot of fairly common attractive native plants in Delaware, and sometimes these get taken for granted. This is a pity, as several have some surprises in store if you look at them closely. Trout Lilies are a perennial often found growing in clumps which get their name because their mottled leaves resemble the sides of a Brook Trout, a freshwater fish. However, they take between 4 and 7 years to mature so the great majority of the lilies you see don’t produce a flower and have just a single leaf (top photo). Only the older, flowering plants have two leaves (second top). The beautiful nodding Lily flowers are harder to find but tend to occur in small colonies which are often visited by insects (bottom photos).

The familiar Mayapple has a similar subtlety. This distinctive umbrella-shaped wildflower of shady forest floors is often found in dense clusters of what look like identical plants, but if you look closely you will see that some have a forked, Y-shaped stem whereas most have just a single stem (below). Only the Y-shaped stems produce a flower then later the apple-like fruit. Mayapples are actually misnamed, as in May they still only have the white flower, which is found in the base of the fork. The hanging ‘apple’ doesn’t appear until later in the summer, and despite the name, is not pleasant to eat and may even be poisonous so we do not recommend that you try it.

Delaware is blessed with a kaleidoscope of beautiful native wildflowers in our area and below are a few of my favorites (from top, Virginia Bluebell, Cardinal Flower, Great Lobelia, Butterfly Weed).

These beautiful wildflowers are available at a reasonable price at the Native Plant Sale so if you want to able to observe these natural wonders in your own back yard just come on by. As well as their visual appeal they are popular with beneficial pollinator insects like bees and butterflies, so now you can have an idyllic native garden and help nature at the same time!

The Plant Sale is held at Coverdale Farm Preserve (543 Way Rd, Greenville, Delaware) Thursday May 3rdand Friday May 4th from 3pm to 7pm (member days) and Saturday May 5th (10am – 4pm) and Sunday May 6th (11am – 3pm) (open to public). Free admission if you just want to come and browse! Credit cards, checks and cash accepted. Click on the link below for more details.

http://www.delawarenaturesociety.org/NativePlantSale#.WuijZi7wa7Q

By Ian Stewart

Delaware Nature Society has over 200 nest boxes spread around the properties we own or help manage which we installed to provide nest sites for a variety of birds. Every summer these boxes are monitored by a team of volunteers who track over 100 nesting attempts by 5-6 bird species (and we are always looking for more people to help with this – please get in touch if you’d like to get involved!). You’d be wrong to think the boxes stand idle throughout the winter however – it’s just that most of the action now takes place at night!

Several birds often roost in them during the winter, including Screech Owls, Eastern Bluebirds and some woodpeckers, which they probably do to protect them from the elements such as wind and rain. It is likely several degrees warmer inside a nest box than outside of it and for a small bird on a very cold night this could be the difference between life and death. Bluebirds take this a little further and are famous for ‘bundling’, where several birds squeeze into the same box for the night, probably keeping each other warm with their body heat.

A male bluebird entering a nest box

A male bluebird entering a nest box in winter

This year we’re making a special effort to check our boxes during the winter too. Sometimes it’s obvious that birds have been roosting in our boxes as they leave their droppings behind. The droppings in the photo below were almost certainly from a bluebird that has been eating Oriental Bittersweet. Bluebirds usually eat insects but at this time of year these are hard to find so they switch their diet to berries, and this exotic invasive vine is one of the few local plants that still has berries on it in February. You can help bluebirds in winter by planting berry-producing native bushes and shrubs such as Winterberry, Viburnums and Hollies. We will be following these boxes all through the year to see if bluebirds end up nesting in the same boxes that were used in winter.

Bluebird droppings inside a nest box

Bluebird droppings show they have been using this nest box

It’s also worth checking nest boxes in winter for less-desirable occupants. About 10% of our nest boxes are occupied by white-footed or deer mice during the winter. These nocturnal mice build fluffy nests inside boxes and sleep in them during the day. We always dump out mice and their nests during the winter, which may seem unkind but if left in place their urine and feces can damage boxes or carry disease, and birds won’t use boxes already occupied by mice. If you do this yourself, don’t use your hands to dislodge mice and their nests in case you pick up any disease or get bitten, but instead gently ease out the box contents with a stout stick.

Two deer mice fast asleep in this box

Two deer mice fast asleep in this box

This box at Coverdale Farm Preserve contained a furry nest with no fewer than 15 uneaten hickory nuts, which was interesting as this is not a common tree at the Preserve. These had probably been stored in the box by a Flying Squirrel, a nocturnal mammal which does not hibernate and requires food all winter. The squirrel cached the nuts here to provide a food supply for later in the winter, so to be sure the little guy wouldn’t go hungry we left the nuts below the box.

Hickory nuts cached in this nest box by a flying squirrel

Hickory nuts cached in this nest box by a flying squirrel

So just because you never see anything going inside your nest boxes in winter, don’t assume they aren’t being used!