Gregory M. Plunkett, Ph.D. is Director and Curator, Cullman Program for Molecular Systematics
Giant Hogweed (Image from New York State Department of Transportation’s Dangerous Roadside Plants page)
From the recentnewsreports, you’d think that New Yorkers had better fly south to escape the onslaught of the diabolical giant hogweed. Even its name evokes a sort of dread, and we are reminded of the stories of “killer bees” from the 1990s.
The giant hogweed plant (know scientifically as Heracleum mantegazzianum) is native to the Caucasus, a mountainous region that separates Europe from Asia. Like so many invasive plants, this species was originally imported to North America as a garden ornamental. It’s easy to see why. The plant is an attractive, gigantic herb, reaching up to ten feet tall in just a few months, topped by huge, umbrella-like spreads with hundreds of tiny white flowers. As a consequence, each plant can make hundreds or even thousands of seeds. Inevitably, this exotic species started to jump garden fences. In our region, the plant was first introduced to Rochester, N.Y. sometime before 1920. Since then, it has been steadily colonizing New York State (see the DEC map here) and it is now approaching New York City.
Why all the fuss? Well, it turns out that giant hogweed produces a sap containing some nasty chemicals called “furanocoumarins”. These compounds easily pass into our skin cells and bind to the DNA inside. Once inside the skin, one additional ingredient is needed to activate the toxin: sunlight. Exposed to the sun, these chemicals kill the affected cells, resulting in a reaction called phytophotodermatitis. This is a nasty, itchy rash that causes discoloration of the skin (from red to dark purple) that can last for months or even years. In severe cases, it can progress, turning into large blisters that mimic second-degree burns. If the plant’s sap reaches the sensitive tissue of your eyes, this blistering could result in scarring and blindness. Yet, as bad as this rash can be, furanocoumarins have been used medicinally as a remedy for psoriasis (where it prevents cell proliferation) and vitiligo (where it darkens depigmented skin).
Most victims of giant hogweed are affected while working in weedy patches, where they are exposed directly to the sap while removing plants by hand or cutting them down using a weed-whacker or lawn mower. The good news: we have expert advice from http://www.backyardboss.net/best-string-trimmer-reviews/, their blog gave us real insight. Giant hogweed is easy to see (it’s ten feet tall, after all), and you must be exposed to both the sap and sunlight. As a result, there are two ways to prevent this nasty rash: avoid exposure to the plant, especially its sap by wearing long pants, long-sleeved shirts, and protective eyewear in areas where giant hogweed grows (unlike the NYS DOT workers above), and avoid exposure of your skin to the sun for the next few days if you do accidentally touch it.
As it turns out, giant hogweed is not the only plant that can cause phytophotodermatitis. Many of its relatives in the plant family Umbelliferae also produce furanocoumarins, including carrots, parsnips, fennel, and celery, but the level of toxins in these species are typically lower. The same family includes other toxic plants, such as poison hemlock, as well as many useful herbs and spices like dill, parsley, cilantro/coriander, and caraway. The same class of compound are produced in completely unrelated plants, too, such as the wild relatives of tomatoes and strawberries, and in the rinds of lemons and limes. You may have heard of the dangers of making lemonade in the sunshine!
Finally, before you sell the house in New York and move to Florida, remember that we have already learned to deal with other nasty plants that cause terrible skin rashes and even blindness, including poison ivy and stinging nettles. Even though these native plants are harder to recognize, we have learned to deal with them. And one last reminder before you sell you house and head for Florida: We New Yorkers may have to deal with snow and giant hogweed, but at least we don’t have alligators, fire ants, and killer bees!
This peony is named 'Kevin'. Not that far off from a moss named 'Mark'.
I have been editing a lot of articles for nybg.org recently that involve long lists of the names of the many hybrids and cultivars we keep on Garden grounds. Anyone who has ever edited a long list in HTML can tell you that it is one of those tasks where it really is okay to let the mind wander a little. It has given me a lot of time to daydream about what kind of plant I would like to have named after me, if, you know, someday I just happen to meet the right hybridizer …. And I know I’m not alone in thinking about this, because when I posed the question yesterday on Twitter, “What would you most like to have named after you? A rose? A daylily? A hosta? Tell us!” the responses came fast and furious.
BloominChick shows her wild side in dreaming of “Something hardy, strong & beautiful. A tiger/wild Lily? (Those striking orange ones).”
There were also votes for a hosta, an orchid, a waterlily, and a butterfly (not technically a plant, but since so many plants can’t live without flowers, we’ll allow it).
Recycled drain pipes used as planters in the Hampshire (U.K.) Garden of Pauline Thomas
By now your garden should be ablaze with color. If it’s not, and you’re finding that you have unsightly gaps in your border, don’t panic! There is still plenty of time for an easy fix: Add a container display to your garden! Don’t limit your container plantings only to the patio though, containers are also a great way to jazz-up any dull or quiet beds or borders you might have.
An attractive container display starts with a good foundation–a good looking container. Many containers these days are made of synthetic materials like poly resin and fiberglass. These materials are often transformed into believable reproductions of classic containers. Find one that suits your gardening style.
Wooden planters on the New York balcony of Devin A. Brown
If you are in the market for a rustic looking container try wood, faux wood or faux stone. If you prefer a more elegant look, then invest in terra cotta, faux terra cotta, reconstituted stone, or faux cast iron. Artistic souls will welcome the stunning array of colorful glazed pots as well as colorful lightweight synthetic substitutes that seem to be available everywhere these days. A few years ago I fell madly in love with a fiberglass reproduction of a bronze container that looked durable as well as lavish.
Colorful pots full of succlents in the Dallas patio garden of Shawn Ashmore
Maintaining appropriate moisture levels can be a challenge when gardening in containers, particularly if you like to escape for a few days during the summer. As common sense would dictate, the larger the container, the easier it is to keep it well-watered. There are many self-watering containers or contraptions on the market that you can outfit your container with. They are essentially water reservoirs that hold the water in the bottom of the container and slowly release it into the mix.
Another viable option is to add some of water retaining polymers or hydrogels to your potting mix. These polymers grab water from the soil, expand as they hydrate, hold onto the moisture, and then release it when the surrounding potting medium starts to dry. Friends of mine who plant narrow window boxes swear by them. Two brands that are easy to find are Terra Sorb® and Soil Moist™.
Whether you are placing your container in the garden or on your patio it is always advisable to raise it up onto bricks, blocks or feet to allow for good drainage. Next week we will take a look at some candidates for filling your lovely new containers.
Seasonal Walk is an exuberant celebration of the seasons. Never the same two weeks in a row, this beautiful garden was designed by the famous landscape designers Piet Oudolf and Jacqueline van der Kloet. Bordering the Garden Cafe and the Enid A. Haupt Conservatory, Seasonal Walk in the early Summer is a dazzling display of sun-loving dahlias, garden phlox, and a range of lilies. At the eastern end of the walk an assortment of plants that thrive in the shade like ferns and astilbes can be found under a stand of trees. Keep your eyes open for the many different kinds of butterflies that flock to this colorful, beautiful garden.
