Month: April 2010

Newsy Note: Japanese Barberry

Look into the woods of Connecticut during early spring and you’ll likely notice stands of low-growing shrubs leafing out in an almost eerie lime-green. It’s likely Japanese barberry (Berberis thunbergii DC) at its worst – invading our woodlands.

 Japanese barberry 4-29-10 These imports from Japan now dominate large expanses of woodland undergrowth and crowd out native trees and plants – reason enough to find the thorny invaders objectionable. But scientists have uncovered more rationale to abhor the shrub; dense Japanese barberry thickets serve as favorable breeding grounds for Lyme disease-carrying ticks.

Scott C. Williams, PhD, and colleagues at The Connecticut Agricultural Experiment Station in New Haven compared three plots of land in Connecticut. They left one heavily infested Japanese barberry plot alone. In a second plot Williams’ team controlled barberry thickets by cutting the shrubs down, then killing late-summer new growth with a propane torch. Their third study plot had no evidence of Japanese barberry.

William’s team spent two years trapping and recording the numbers of white-footed mice in each plot, as well as the number of ticks feeding on the mice. They found the uncontrolled thicket of Japanese barberry averaged 6-to 7-times more ticks over the two years than the other two plots.

Barberry thickets give mice protection from predators serve host to one part of a tick’s life cycle. William’s group speculates the early spring leaf-out of barberry thickets creates the humid ground-level micro-climate in which ticks thrive. These two factors seem to give ticks a good jump start. Once done feeding on mice, barberry shrubs provide ticks the avenue – so to speak – necessary for the little blood suckers to complete another life-cycle phase. By climbing to the upper regions of the barberry shrubs they are able to catch a ride on passing deer.

Now if deer ate Japanese barberry, I doubt the shrubs would be so prevalent. But deer don’t like the thorny invaders any more than humans, so Japanese barberry thrives, mice thrive, ticks thrive, and deer certainly thrive in Connecticut woodlands. The combination may create the perfect Lyme-disease storm.

But before you grab a machete or other instrument of destruction to attack barberry thickets, understand the shrub is not easily controlled. Williams suggests a two-step process:

· First mechanically remove the above ground portion of the shrub in spring or early summer. For heavy stands a brush saw or tractor-mounted brush hog works best.

· Then allow the shrub to use some reserved energy to shoot-up new growth. In late summer kill new growth with either an herbicide or a propane torch.

Japanese barberry2-4-29-10 The second step is vital. Left alone the shrubs will grow back “with increased vigor,” Williams told me in an email. Forget to follow up and after one growing season your cut-down barberry thicket will look like you’ve done nothing.

Hand pulling might work if you are lucky enough to find just a few small barberry shrubs in your area. “It’s a heck of a lot easier to get rid of them before they form an impenetrable thicket,” Williams said. But “any little rootlet left in the soil has the potential to re-sprout into a mature plant.”

Again, regular vigilance is needed to eradicate Japanese barberry.

The Invasive Plant Management Guide from UConn offers more detailed Japanese barberry obliteration methods. Click on the Woody Plant link, then on Japanese Barberry. Additional photos from Invasive Plants of the Eastern U.S. will give you a better idea of the shrub’s many stages, including the bright red berry stage. Birds eat the berries, do their bird do-do from whatever perch they choose, and voila, barberry spreads.

Even more photos and links to information on Japanese barberry’s impact in other state comes from and the USDA Plants database.

Massachusetts prohibits the sale of Japanese barberry. There’s some move toward a voluntary ban on sales of certain Japanese barberry cultivars in Connecticut. All homeowners, gardeners, and landscapers should avoid buying and planting Japanese barberry.

Personally, I don’t understand why anyone wants these shrubs in their landscape – I have yet to see a cultivar I find attractive. Considering the negatives, doesn’t it make more sense to just avoid planting Japanese barberry?

Stay tuned. Debbie, at A Garden of Possibilities, plans to alert readers on any ban updates in Connecticut, and Williams told me he is in the process of compiling information from continued samplings of the original plots. His team has also continued to manage barberry thickets using only propane torching and he plans to report on these findings as well.

Spring blooms early in Connecticut

poets narcissus5 Spring seems to be in a hurry here in southern CT, as if she is late for an appointment with Summer.  It’s now nearing the end of April and all my early daffodils and naricssi have finished or nearly finished blooming and my Poet’s Daffodils (Narcissus poeticus recurvus) are in full bloom.  Yet last year, I posted about an early narcissi bouquet of yellow tinged blossoms on April 22, 2009 and my Poet’s were still at least a couple of weeks from bloom.

When I investigated further I pulled up a May 12, 2009 post about a lilac bouquet. This year lilacs are blooming now, on April 27. Early yes, but without the vigor and numbers of blooms they produced last year.

For mid-May 2009’s Garden Bloggers’ Bloom Day I posted photos of lilac, sweet woodruff, Eastern Red Columbine, and azaleas.  In 2010, all the same are in bloom at the end of April.

So what gives? According to the National Oceanic and Atmospheric Administration – better known as NOAA – March 2010 was the warmest on record.  The January through March period was the 4th warmest. No wonder Spring sprung early. Globally, the land and oceans were both warmer by about 1.2 degrees F over the twentieth century average.

In New England, Rhode Island recorded the warmest March on record; Maine the second warmest; New Hampshire the third; and Massachusetts, Connecticut, and Vermont the fifth.

But don’t throw those tender plants outside just yet. There’s still a chance for plant-stunting chills in even the most southern regions of New England.  It’s best to keep your tomatoes, peppers, eggplant, coleus, houseplants, and other tender greens inside for at least a couple more weeks.  And when you do move them out, do so gradually … perhaps to a covered porch protected from direct sun.  Then, after a week or so, expose them to a little more sun each day until they are accustomed to the sun’s strong rays.  And don’t forget to check their water needs daily.

Seeds of more hardy plants – peas, lettuce and other greens, radish, onions (sets too), etc. – can be planted outside either directly in the ground or in pots.  They can take, and even benefit from a little chill.

poets narcissus9With all the warm hugs spring has offered my region, I wonder what the summer will bring.  In keeping with warm spring temps, we’ve already had a good summer-style thunderstorm or two – along with the phenomenal rainbow shown in my previous post – but we’ve also had winter/spring style cold fronts move through to remind us not to get too comfy with the warmth just yet – we’re still wearing sweaters and grudgingly allowing the furnace to run.  Still, overall toasty temps have stretched out to the Atlantic so it’s now bathed in warmer than usual waters.  Warm ocean waters means greater chances for hurricanes, and that’s just what the good scientists at Colorado State University have predicted.  Though I still don’t understand why hurricane forecasts come from a land-locked mountain state rather than an eastern coastal one. But hey, I don’t make up the rules … I just ask questions and offer photos of my favorite flowers.

poets narcissis3