Invasive Plants

See also: Herbaceous Perennials
Hemerocallis fulva, tawny or orange daylily, has been planted in American gardens forever it seems. As you drive rural roads during early summer, the flashes of orange you see along the side of the road or in abandoned rural farmsteads are almost certainly Hemerocallis fulva (or perhaps Asclepias tuberosa - butterfly weed).

Hemerocallis fulva flower

Hemerocallis fulva flower detail. Click for larger.

Watch out, as Hemerocallis fulva will take over a bed completely. Choose where you plant orange daylily in the garden wisely, in places where it may spread and colonize the area completely. If you need to control erosion or have a weedy spot, tawny daylily is an apt choice.

Continue reading ‘Hemerocallis fulva – Tawny Daylily’

See also: Herbaceous Perennials
Yellow flag iris (Iris pseudacorus) is a highly adaptable and easy to grow perennial that needs sun to flower at its best. It is hard to resist the impeccable clarity and tone of the flowers. In a world where yellow flowers inhabit the landscape in all seasons, yellow flag iris is one of the finest in the land. It is also considered highly invasive in some parts.

yellow flag iris

Yellow flag iris - Iris pseudacorus. Click for larger.

Many gardeners drop the 'iris' from the name and merely refer to Iris pseudacorus as 'yellow flag'. The first time I remember seeing yellow flag iris was at the edge of a small lake: a dense colony eight feet across with those pure yellow flowers held aloft like a king's banner.

Continue reading ‘Yellow Flag Iris & What We (Don’t) Know About Climate Change’

See also: Herbaceous Perennials
(Chrysanthemum leucanthemum) Oxyeye daisy's golden disc surrounded by white rays is a form familiar to us all. It is a safe bet the oxeye daisy or similar flowers such as Ryan Gainey's daisy have been the models for millions of childhood drawings.

oxeye daisy

Oxeye Daisy. Click for larger.

Inspired by daisies. Click for larger.

Inspired by daisies (and perhaps clematis), a drawing by Flynne. Click for larger.

Oxeye daisy is a perennial hardy all the way to USDA zone 3, and it is not frost tender. It is easy to grow with a few caveats...

Continue reading ‘Oxeye Daisy – C. leucanthemum’

See also: Herbaceous Perennials
Lunaria annua, money plant, is a biennial that looks to my eyes like a woodland plant native to America. Lunaria however is most definitely not native, having been introduced from Asia. Whether it can be considered invasive or not is a matter of some minor debate.

Lunaria annua

Lunaria annua in the woodland garden. Click for larger.

Is it possible for a plant to be considered mildy invasive I wonder? Oregon and Washington definitely are keeping a wary eye on Lunaria annua. Considering there are many worthy candidates for our gardens, I would suggest not planting Lunaria annua in a garden or woodland setting.

There is not consensus about the true threat of Lunaria to native ecosystems. It is a pity, because Lunaria is a charming plant, with gentle purple flowers above sturdy stems in the woodland landscape.

Continue reading ‘Lunaria annua – Money Plant’

Akebia quinata, commonly known as five-leaf akebia or chocolate vine, is considered locally invasive by many environmental groups.

I would add that Akebia quinata should also be considered a large-scale invasive. The bottom-line is that there are many other aggressive vines one can plant (hops vine anyone?) that are not dangerous to native plant populations. Five-leaf akebia is not recommended as a suitable garden or landscape specimen.

chocolate vine

Image by Angela Collins. Click for larger view.

Locally vs. Widespread Invasive Plants

I tend to think of invasive plants as either local or widespread threats. For example, many bamboos spread aggressively via rhizomes to invade any suitable ground within the immediate area. This behavior is aggravating to many gardeners, but bamboo is not generally considered an environmental danger.

When evaluating if a plant is potentially disruptive to ecosystems consider whether it spreads via seed dispersal. The most dangerous plants to the environment are highly adaptable aggressive non-natives whose seeds are dispersed by birds or wind.

Continue reading ‘Five-Leaf Akebia (Chocolate Vine) – Invasive’