Tag Archives: invasives

November Walk On Campus

Yesterday was Garden Bloggers Foliage Day (GBFD) over at Christina’s which always highlights some interesting leaf, texture and color combinations that can carry the garden year-round. Busy with Thanksgiving and finding my own foliage pretty unremarkable this month, I did not prepare a GBFD entry this time, but today during a morning walk that included a visit to Coker Arboretum, I had a second chance to concentrate on autumn foliage.

Coker Arboretum

Just five and a half miles away, Coker Arboretum is a five-acre treasure on the campus of the University of North Carolina at Chapel Hill (my alma mater). It dates back to 1903 when UNC’s first Botany professor, Dr. William Coker, began creating an outdoor lab to study native trees and shrubs. During the 1920s through the 1940s Dr. Coker extended the scope of the garden to include East Asian species, which correspond closely to many plants in North Carolina.

In spring there are beautiful displays of daffodils, in early fall, red spider lilies. Today the majestic trees dominated the landscape, including numerous conifers and magnolias, American beech, Northern catalpa, American Elm, Japanese Maple, pond-cypress and bald-cypress.

Taxodium distichum (Bald Cypress)

This morning a pair of Ginkgos were especially colorful.

Ginkgos At Coker Arboretum

Fallen leaves from the Ginkgos covered the lawn, pathway and the bench too. When school is in session someone is nearly always sitting and reading on the teak benches that are scattered throughout the arboretum.

Carpet of Ginkgo Leaves

The slender tree in front in the picture above is a western Florida native, Magnolia ashei (Ashe’s Magnolia).The USDA plants profile lists this deciduous magnolia as endangered.

Magnolia ashei (Ashe’s Magnolia)-western Florida

Firmiana simplex (Chinese Parasol-tree) is fascinating in any season, but today the white bark seemed very stark.

Firmiana simplex (Chinese Parasol-tree)

Chinese Parasol leaves form dense shade in the summer. This tree is listed as invasive in some states, but not here as far as I could determine. Coker Arboretum now is now under the management of the North Carolina Botanical Garden (NCBG), whose staff is well qualified to evaluate this and all the plantings here.

Huge leaves of Firmiana simplex (Chinese Parasol-tree)

Coker Arboretum’s collection is extensive and there are many more interesting trees and shrubs to share. This final scene for today shows the bright red blossoms of Camellia sasanqua.

Camellia sasanqua

Physostegia virginiana (Obedient Plant)

This afternoon I discovered a bloom of Physostegia virginiana (Obedient Plant) rising up through a mound of Nepeta ‘Walker’s Low’ (Catmint) in the northern border.

Physostegia virginiana (Obedient Plant)

For a couple of years I have been battling this native plant, one that was well-behaved in my previous garden. Given to me by a dear relative many years ago, I brought it along to the current garden cheerfully, believing it to be a wonderful plant.

It blooms in late summer when few other things can be so readily counted upon. It charms everyone, young and old, by having bendable flowers—when touched they remain in the position they are bent (thus the name Obedient Plant).

Physostegia virginiana (Obedient Plant)

Though it remained well-contained in my old garden, in the much richer prepared soil of my current one, this perennial starting establishing itself too heartily, spreading by rhizomes throughout the entire northern border.

It seems a shame to pull out something that is so pretty and so enjoyed by this bee, but I guess I will have to toughen up and remove this plant or face the consequences. Fortunately the bee should be able to find some other nourishing plants within the same border.

Italian Arum. Surprise!

Protected and somewhat obscured by a gardenia, an Italian Arum thrives. Though not obvious at first, it sits tucked away under the large shrub, awaiting discovery from a passer-by.

The hastate or arrow-shaped leaves of Arum italicum (Italian Arum) add textural interest this time of year. The shiny deep green leaves, accentuated by light, vein-like markings, emerged in early fall (October) and remained evergreen all winter.

The garden was new and had very little shade when this plant was first added, so the arum was sited on the northern side of the house in a narrow strip along the foundation. For a couple of years it made a nice companion plant to a large clump of hostas, filling in when the hostas died back each year. The hostas are long gone (taken by drought, not deer, surprisingly) and the now mature foundation shrubs fully occupy the slender space.

I had planned to divide the Italian Arum this year and move some into the main garden where it might be more noticeable, to create a more effective display. In researching today how to divide Italian Arum I have learned that would not be wise. Unfortunately this plant is not native, rather it comes from Africa, Asia and Europe. It is listed as invasive in some parts of the U.S., including the nearby state of Virginia. Some North Carolina gardeners report Italian Arum as extremely difficult to eradicate and warn against planting it.

So this started out as a post about the surprise of coming upon a lovely and unusual plant such as Arum Italicum in the garden. It was supposed to end this way:

The arum certainly is fun where it exists now, lending that element of the unexpected. Walking by its hiding place, missing it at first, then glimpsing it at last and noticing its amazing surprise of shape and pattern, one is reminded of the joy plants can bring.

Arum Italicum (Italian Arum) held an even bigger garden surprise than I knew. This plant has always behaved well in this garden but if its seeds can spread and cause problems, I will have to seek some expert help for clarification and advice.

Meanwhile at least Arum Italicum did provide an opportunity to learn the word hastate:

Hastate, spear-shaped (hastata): Pointed, with barbs, shaped like a spear point, with flaring pointed lobes at the base
“Leaf shape.” Wikipedia, The Free Encyclopedia. Wikimedia Foundation, Inc.. Dec 2011. Web. 1 Feb 2012.

Swamp Sunflower

Near where the Rudbeckia ‘Irish Eyes’ performed so poorly this year, I spotted a pretty bit of yellow in the garden.

Thinking I had overlooked a rudbeckia stalk or two when cleaning up that area a few weeks ago, I optimistically went out to investigate. To my dismay I immediately recognized the beautiful golden yellow flower was not ‘Irish Eyes’ at all.

Swamp Sunflower. It was swamp sunflower again.  A tall perennial that grows along roadsides, I innocently accepted one from a friend at a plant exchange possibly eight years ago.

Soon I learned that under the right conditions, swamp sunflower can spread by underground rhizomes and be potentially invasive. This perennial sunflower quickly became much too happy in the garden, so I have been pulling it out for years.

It does have a pretty flower though. A few days. I will give it just a few days.

Hot and Cold, Weed Or Not


The predicted rain finally arrived late last night and continued steadily until after daybreak.  It is 37 degrees now and temperatures are expected to reach only 43.  Today’s brisk chill caps off a cool week that contrasted sharply with the sunny, eighty-degree days from the week before when warm air seemed destined to stay.

Bishops’ Weed

Emerging Bishops' Weed - March 26, 2011

Bishops’ Weed
Aegopodium podagraria

During a short tour around the garden yesterday I was reminded of my plans to deal with the Bishops’ Weed this year.

This unruly member of the garden’s plant collection is back and filling out quickly.

Bishops’ Weed is rather pretty, variegated ground cover that brightens up a rather difficult narrow space which otherwise would probably just be brown mulch. It has a light green color and a delicate, white lacy flower.

Bishops' Weed - May 2006

A friend passed along Bishops’ Weed when I first began perennial gardening at my former home. This ground cover survived in the shade that dominated much of my old garden where it mostly stayed put.  I do not remember it being a problem and must not have thought so because, when it came time to move and start a new garden, the Bishops’ Weed came too.

Though my current garden space is mostly sunny, I found a partially shaded spot for this plant on the rather narrow, north side bed between my house and the neighboring driveway. It is a ground cover so I expected it to spread, but was unprepared for how aggressively it grew.

Bishops’ Weed spreads by rhizomes and I have learned since it can become invasive. One might think the name would be a tip-off, but not necessarily.  Consider Eutrochium purpureum or Joe-Pye Weed, which is a native plant and one frequently recommended as a favorite garden addition in this area.

Eastern Columbine and Bishops' Weed - April 2009

Anyway, I searched several reference sites for more information on Bishops’ Weed, but did not find it on these invasive warnings for this area:

I cannot remember if I have seen Bishops’ Weed growing in other gardens I have visited. I will have to check around more to see if it is a conservation worry or just a bit of a nuisance in my own little world.