Category Archives: New England invasive plants

Backyard Natives: Wild Cranesbill

Cranesbill has long been a staple plant of New England gardens for its pretty spring flowers and low ground-covering habit, but despite common names such as New Hampshire Purple, most of our garden cranesbills hail from Europe and Western Asia.wild cranesbill geranium maculatum

If you’re looking for easy and non-aggressive native plants to fill your garden with color and seasonal interest, our eastern native species Spotted Cranesbill/Wild Geranium (Geranium maculatum) is worth growing if you have an area with moist soil and a bit of late-summer shade.

Wild Cranesbill blooms with cheery pink flowers in late spring, and its distinctive toothed lobed foliage add texture to a cottage or rock garden, a woodland edge, or nestled into gaps between shrubs in a border. With a long history of medicinal usages, this plant belongs in every modern herb garden.

Wild Cranesbill was once abundant along country roads in central Massachusetts, but the steady invasion of aggressive non-native plant species means its cheerful spring presence may become a thing of the past. By growing it in your own gardens, you can help maintain local populations of this hardy and (hopefully) resilient plant that (like many other native plants) is under threat in the wild.

IMG_2831

Wild cranesbill still grows on the edges of a nearby roadside — surrounded by exotic weeds including Multiflora Rose, Garlic Mustard and European agricultural grasses.

Several years ago, I collected seeds from these roadside plants and grew them in my own gardens, where they thrive tucked between larger shrubs in the leaf-enriched soils along the stream’s edge. Now that the dreaded invasive plant Garlic-Mustard has reached our neighborhood, I’m not sure if the wild roadside geraniums will survive the onslaught.

Garlic-Mustard: Another Threat to Woodland Biodiversity

DCF 1.0

If you see this plant with small white flowers and scalloped leaf edges, yank it immediately! If it’s flowering, cut off and throw away the flower heads before the plant goes to seed!

Garlic-Mustard (Alliaria petiolata) was rarely seen in this part of Massachusetts even 10 years ago. Introduced into the USA from Europe and Asia as an edible plant and kitchen herb, this plant has spread across the North American continent, seeding itself quickly into disturbed areas to form dense colonies. Garlic-Mustard is especially dangerous to eastern forests, because of its shade tolerance, and because its roots produce chemicals that kill the microbial soil life essential to the growth of native trees and understory plants.

I first noticed Garlic-Mustard growing on a roadside in our neighborhood in 2007, and since then have watched in dismay as it has quickly spread (by seeds distributed by wind and wildlife) through our river valley. If you see this plant on your property, act quickly before it can spread further. It is a biennial plant, so it blooms in its second year from seed, which is when most people tend to notice it. The best approach is to pull up any plants by the roots if they are first-year plants. If the plants are flowering or have already bloomed, cut off their flower heads before their seeds can disperse. Each plant can contain up to 6000 seeds which remain viable for at least 5 years, so throw these away in the trash and do not compost them! Click here for more pictures and information on Garlic Mustard.

Virginia Rose

Have you always loved roses, but hate the spraying, fertilizing, watering and pruning they require to keep them from looking a mess? Please meet the lovely Virginia rose (Rosa virginiana). Unlike its highly-bred, cultivated cousins (hybrid tea roses and modern cultivars of climbing roses) this native eastern rose is hardy to the coldest parts of New England, grows happily in almost any soil, needs little to to no irrigation except for rainwater, and blooms its head off through June with pink flowers with the most heavenly fragrance. Not to mention, their beautiful red fruits (hips) persist right through the winter, feeding birds and providing winter interest when the landscape is otherwise white and brown. What’s not to love?

DCF 1.0
IMG_4918 virginia rose hip closeup snow reduced

Most Virginia roses bloom in light or medium pink, although there are white-flowering cultivars available too (I’ve not had good experience with the white-flowering form, however). Their flowers might not have the fluffy allure of the larger double-formed hybrids, but their single-flowering form makes them much more attractive to butterflies and other pollinators, who don’t have to fight their way through many layers of petals to access the sweet nectar and pollen at the center of the flower. And did I mention its fragrance?

When it’s happy, which is in any decent soil with good drainage and plenty of sunshine, Virginia rose will spread fairly rapidly within just a few years, so if you have a large area you’d like to fill in quickly with a wildlife-friendly native plant, Virginia makes a great choice.

In bloom, a pink tapestry of Virginia rose mingles beautifully with foxglove, cranesbill and other late spring bloomers and will form a low, thorny hedge that offers excellent year-round predator protection for the birds visiting your gardens. This sunny hillside of our farm was planted with a single container of Virginia rose in 2006, and by June 2009 it had happily spread to form a sizeable thicket:

IMG_3641 virginia rose thicket reduced

As you might imagine, its spreading habit (through underground roots that snake in every direction) makes Virginia rose unsuitable for small gardens, where its roots will eventually take over surrounding plants and form dense canes that shade them out. A better-behaved but just as pretty wild rose is Virginia’s closest cousin, Carolina or pasture rose (R. carolina) which spreads by slowly enlarging clumps rather than spreading roots.

In the thicket above, an annual mowing stops Virginia rose runners from spreading into the adjacent lawn, but you can also contain its advancing roots with a hard root pruning every few years with a sharp shovel. A driveway also makes a good boundary, as long as you don’t use large amounts of salt to de-ice your driveway.

Note: Please let it be known that I would dearly love for the above Virginia rose thicket to spread and cover the entire hill, but hubby has drawn a literal line in the sand (with rocks!) where his lawn cannot be further encroached! I am hoping he won’t notice the line has moved a few times

So planting Virginia rose in beds with other perennials is not a good idea, but in a new planting of a large area, you can interplant with self-seeding annuals, biennials or short-lived perennials to fill the bed for the first few years while the rose spreads….I initially planted the above bed with common sage, purple coneflower, cranesbill, foxglove, cosmos and cleome, and after 4 years, mostly only the foxglove remains in the area, probably because its seedlings are more shade-tolerant than the others. The others I have simply moved to other areas of the garden or given away to friends.

If you’ve grown roses before, you’ll appreciate that Virginia’s foliage is very resistant to most of the common diseases that disfigure roses. Like all roses (wild or cultivated), Japanese beetles love to eat its foliage, but if your plant is healthy and vigorous, it should shrug off any damage. These roses bloom in June in central Massachusetts, and Japanese beetles don’t tend to arrive in large numbers in our area til early July, so by the time the beetles start chewing, you should have other beautiful blooming plants to distract you from a few holes in their leaves.

 Virginia rose canes top out at about 4′, so you should never need to prune them for height, especially because you’d be cutting off one of the plant’s best features, its plump red hips that you barely notice until the first winter snows suddenly bring them to life:

05-21-virginia-rose-thicket-snow

The hips must be pretty sour to taste, because the birds don’t seem to touch them at all during the winter. They disappear around the beginning of spring here, so winter’s deep freezes must sweeten them up a bit, or else late winter birds are too hungry to be picky. I often see their thorny stems used as a temporary hideout by foraging winter birds, who get spooked by hungry hawks hovering around my bird gardens and feeders. The white background makes tiny birds much more visible to larger predators (my dogs will confirm this because they constantly mistake them for chipmunks!) but even a cat is unlike to risk those nasty thorns and go in after them…

If your garden conditions are boggy or wet, the best native roses for garden use are swamp rose (R. palustris) and New England rose (R. nitida), although these bloom a little later than the field roses in summer.

If you look, you may still find native roses growing wild in natural areas. More often than not, though, roses that you see in the wild are the invasive multiflora rose (R. multiflora), which is often assumed to be native but is an introduced rose from Asia that has been steadily overtaking old fields in New England for decades:

19-x Multiflora rose closeup cropped reduced Although birds do eat their berries, multiflora rose has a highly negative impact on its surroundings, forming enormous thickets that crowd out the native plants that underpin balanced and healthy ecosystems. Chances are, if you see a large, fragrant sprawling wild rose with white flowers and arching stems, it’s multiflora rose. Removing these from your property can be a great contribution to protecting local biodiversity…you can either replant with one of our native New England roses, or use the “wait, weed and watch” approach, which means simply rooting out any remaining multiflora canes that pop up over time, and allowing any native plants that are still hanging on to make a comeback.

If you try the wait, weed and watch approach, be prepared for a funny thing to happen. You’ll begin to notice an increasing variety of birds, butterflies and other interesting wildlife that visit your naturalized area, many more so than your more cultivated garden areas, and eventually you will realize that your wildlife garden, with all the life it attracts, is your most beautiful and favorite garden of them all…

** BY THE WAY ** Apologies to my email blog subscribers who received a half-written article on Wednesday by email – I hit the “Publish” button instead of the “Save” button and the article went out as is  {deep embarrassment}. The complete article is available here: Gimme Shelter…for the Birds

Should I Pull This Plant?

I hear it all the time. “Should I pull this plant? I’m not sure if I like it…”  The answer usually is….it depends. I have some clients who are passionate about restoring their landscape with native plants in order to help rebuild lost or damaged local ecosystems. For them, the answer is easy. If it’s not native, yes, pull it up and replace with a native plant. But what if your property already has many nice (and expensive) landscape plants and you’re not sure whether they’re worth keeping? As a habitat gardener, you can decide whether to keep or remove a plant by answering a few key questions:

is it listed as an invasive plant in Massachusetts? If yes, definitely remove it to make room for native plants, who may be capable of recolonizing the area. Or, replace it with a native plant suitable for your garden conditions. Invasive non-native plants are a major threat to biodiversity and environmental health. Even if you don’t see a plant behaving aggressively in your own yard, many invasive plants are spread by birds eating their berries or seeds and pooping them into nearby natural areas, where they quickly form colonies that crowd out the native plants essential to local wildlife. See IPANE (Invasive Plants of New England) for the plants that are invasive in New England.chickadee magnolia

is it healthy without needing fertilization or regular watering? If so, it’s well suited to the spot it’s in and won’t need your constant fussing to keep it looking good.

Does it attract birds, butterflies or any other forms of wildlife? Do its flowers provide nectar and pollen for butterflies, bees, hummingbirds and other pollinators to use as a food source? Does it form nutritious berries, seeds, nuts or cones that are an important food source for many birds? Does the plant’s foliage feed caterpillars and other insects that most birds rely upon to feed their young? Does its structure and foliage provide shelter, protection and nesting sites for many birds and other wildlife?

If the plant supplies at least 2 or 3 of these last few attributes, it is wildlife-friendly and you should probably keep it. Its presence supports declining populations of birds and pollinators who help keep our environment in balance.

oie_IMG_5417On our property, we have several areas planted with Cotoneaster, (right) which is a low shrub often used as a groundcover planting in New England lanscapes. It’s not native here, and it’s not what I would call a spectacular plant, but I have never considered removing it because it has its benefits…it thrives along a brick walkway in dry, hot blazing sun without any care or attention from us except for a bit of occasional weeding. Its dense twiggy branching structure, especially when it’s pruned, is a safe place for overwintering songbirds to dive into when they visit our winter bird feeders. Its tiny pink flowers are a magnet to spring pollinators, who are in turn an abundant food source for migrating birds newly arrived from the south. In the fall, pollinated cotoneaster flowers form large red berries, which although I have never seen birds eating them, the berries persist right through winter and disappear in about March, so some hungry creature is eating them when food is scarce!

For a foundation or walkway planting, you can prune cotoneaster into an attractive low hedge that satisfies even the most formal-style gardeners. My own hubby, who loves a crisp, clean Zen-garden style of landscaping, that often – um – clashes with my own more natural style of gardening, loves our cotoneaster hedge because it gives him that controlled look he craves while satisfying my requirement that a plant in such a visible location should not just look good, but also support the wildlife we invite into our backyard habitat.

Natural Invaders

The news from Worcester, Massachusetts in recent weeks is grim. The Asian Longhorned Beetle has been found in the city and has in fact been boring into our trees in stealth for several years, starting a process that could destroy New England’s hardwood forests if left unchecked.

Photo courtesy US Dept. of Agriculture

Photo courtesy US Dept. of Agriculture

Hitchhiking its way to central MA in packing material shipped from the Far East, the beetle’s arrival is an unfortunate side effect of a globalized trade system.

In other areas where this beetle has been found in the US (currently only Chicago, New York and New Jersey), the USDA declared a state of emergency and launched major (and costly) eradication campaigns. The end result? Over thirty thousand hardwood (maple, birch, willow, ash, poplar, sycamore and elm) trees were removed from the areas where the beetles were found. Yikes! That list pretty much includes most of the trees around here! Along with the imported Hemlock Wooly Adelgid pest threatening the Hemlock trees that blanket the Worcester Hills, arborphiles in central MA should be worried.

Imagine a New England devoid of spectacular maple foliage? This is not just about pretty trees, though. The extensive hardwood forests of northern New England sustain an economy built upon the timber industry. Autumn foliage brings millions of tourist dollars into our region. New England’s maple syrup industries rely on Sugar Maple trees, which are already at stress due to damage from road salt and road construction (which damages their shallow root systems). Habitat loss from development is already a serious problem for many New England birds, pollinators, plants and other wildlife who rely on trees and woodlands for part of their life cycle.

If that’s not enough to make you want to hug the nearest hardwood, trees in general provide many environmental benefits. Trees absorb carbon dioxide from the atmosphere, helping to mitigate our carbon emissions and improve air quality. They take up moisture through their roots, preventing soil erosion and flooding in urban and residential areas, and filtering pollutants that would otherwise flow through groundwater directly into our waterways. They also provide shade for homes and buildings, reducing energy costs as well as the urban heat effect. In other words, we need our trees!

Natural Selection Gone Bad
Scientists consider alien, or invasive, species to be one of the major threats to our environment. Invasive species such as the Asian Longhorned Beetle, free of the natural controls of their native lands, proliferate at an unnatural rate in their new home, causing rapid changes to the ecology of an area. Invasive plants, in particular, quickly overwhelm local ecosystems, altering natural environmental processes and patterns of ecological succession. Native plants and animals that have evolved together for thousands of years cannot always adapt to such rapid changes in their habitat, and either suffer extensive losses or disappear altogether.

Many argue that invasive species migration is no different than the natural geographic migration of species that has occurred since life began on this planet. However, the
processes of species migration has traditionally occured through natural events such
as floods and fires, or changes in resource availability due to glacial movement, volcanoes
and earthquakes.

Foreign species are nothing new around here, though. Dodging the emotive issue of whether European colonists to the New World were themselves exotic invaders or a natural migratory evolution, foreign plants and animals have been arriving on these shores since colonists first began settling here many centuries ago. Most of them settled happily into their new home without causing chaos. Think Cabbage, Tomatoes, Lilacs, Peonies, Hollyhocks or European Mountain Ash.

DCF 1.0

Purple Loosestrife taking over a wetland in Leicester, MA.

Some of them, however, have already dramatically altered our landscape. Purple Loosestrife (pictured above), brought here as a garden plant in the 1800s, has jumped the garden gate and spread into wetlands across the northeast. It may be pretty, but Purple Loosestrife is responsible for degrading millions of acres of wetlands, choking out the native vegetation crucial to many forms of aquatic wildlife and birds. The American Chestnut, once the dominant hardwood tree in New England’s forests, was virtually extinct here by 1940, wiped out by a blight carried by by chestnut trees imported from Asia around 1900. The imported chestnuts carried their own disease strains with them, as well as their own immunity. The native chestnut wasn’t so lucky.

Although the arrival of the Asian Longhorned Beetle was accidental, the sad fact is that many of New England’s invasive plants were deliberately brought here for ornamental or agricultural use. Japanese Honeysuckle, Burning Bush (yes, the one you see on every street corner and strip mall) and Japanese Barberry are all popular landscape plants that have potential to degrade our natural areas.  The state of Massachusetts has recently passed legislation to halt the further distribution of these species, and time will tell if this will stem the tide of habitat destruction. Multiflora Rose was brought here for farmers to use as windbreaks, provide erosion control and to supply wildlife habitat. It is now a ubiquitous pest across New England, forming thorny thickets that are difficult to eradicate. In the old field behind our farm, Asiatic Bittersweet, the popular vine for creating holiday wreaths and decorations, has pulled whole stands of trees right down to the ground under the sheer weight of the vines.

One of my clients lives in Holden only a mile from one of the beetle sightings. She and her husband are understandably very worried about losing the large trees that initially attracted them to their shady, mature area of Holden. As the SWAT team descends upon Worcester, examining every tree within the “infestation zone”, she is waiting anxiously for the news of whether she will lose her trees. A helpless feeling, but there is much that we can do as homeowners to protect our unique New England landscape from further invasions.

Know Thy Weeds
Take some time to learn what is growing in your own backyard. Look at the New England Wild Flower Society’s photo gallery of New England invasive plants. You may be shocked to realize how many of your “wild” plants are actually invasive foreign invaders! The idea of removing them may be daunting, but each plant that you remove (and replace with a suitable non-invasive plant or tree) will reduce the damage that continues to undermine the stability of our environment.

Pictured below, Fringetree (Chianonanthus virginicus) makes a great alternative to Autumn Olive, which is a small tree (native to China, imported here during colonial times) that has escaped cultivation and now runs rampant along roadsides and woodland edges. Fringetree blooms in white clouds in spring, and birds like to dine on its dark berries. It blooms best in moist, fertile soil with at least 3-4 hours of sun.

DCF 1.0

A beautiful blooming Fringetree growing in Spencer, MA.