Boneset is a member of the aster family, making it a relative of such well-known plants as goldenrod (Solidago spp.) and New England aster (Symphyotrichum novae-angliae). It sports masses of tiny, fluffy, white flowers that are grouped in flat-topped clusters (known as "corymbs"). One of its identifying features is that the main stem seems to pass right through each pair of leaves on either side of it as if, in each instance, it were sticking out of a hole in the middle of a single leaf (a feature responsible for the species name, perfoliatum). While not an especially attractive plant, it does boast a number of benefits. Its stiff stems make it suitable as a cut flower for fresh arrangements; it also works well in dried arrangements. It attracts butterflies but is not bothered by deer pests.
Perhaps most importantly, boneset thrives in conditions (clayey soil that tends to be soggy) that are too challenging for most plants to grow in. Learn how to take advantage of its tolerance for such conditions and incorporate it into your own landscape.
Botanical Name：Eupatorium perfoliatum
Common Name：Boneset, American boneset, feverwort, thoroughwort
Plant Type：Herbaceous perennial
Mature Size：Maximum 4 to 6 feet tall and 3 to 4 feet wide, but typically 3 feet tall and 1 foot wide in the wild
Sun Exposure：Full sun to partial shade
Soil Type： Average in fertility, average to above-average moisture
Soil pH：6.5 to 7
Bloom Time：July to September
Flower Color：White
Hardiness Zones：3 to 8
Native Area：North America
How to Care for Boneset
You will reduce your maintenance for boneset if you resist the temptation to over-fertilize it. In overly fertile soil it will flop over (especially in a windy spot), thereby necessitating staking.
More difficult to get around is the fact that this clump-forming perennial does spread via underground rhizomes. So it is not advisable to install it in a flower bed where it will be sharing space with other plants: You would end up having to pull out stray boneset plants periodically to prevent them from crowding out other plants.
A better use for boneset is in a rain garden or in a woodland-garden setting where the soil is constantly on the wet side. It is in areas such as these that you can take the best advantage of boneset's tolerance of (or preference for) wet conditions.
Light
Boneset tolerates partial shade. But it will flower better if you give it full sun.
Soil
Tolerant of a range of soil conditions, boneset can be grown in either a sandy soil or a clayey soil. However, since the plant prefers its soil to be constantly moist, be sure to give it extra water if you are growing it in a sandy soil. Sandy soils are like sieves: They do not hold water well.
Water
Do not ever allow the soil of boneset to dry out completely. This is the most important principle in caring for the plant.
Fertilizer
Boneset performs best in a soil with only average fertility. Do not give it too much fertilizer. If you are planting it in garden soil to which you have added compost in the past, you may never need to fertilize boneset.
Varieties of Eupatorium
Closely related to boneset are two other species of Eupatorium:
Purple Joe Pye weed (Eupatorium purpureum)
Spotted Joe Pye weed (Eupatorium maculatum)
Both, like boneset, are native to North America and like to grow in wet ground. But both possess greater ornamental value than boneset, for two reasons:
They are taller plants (up to 7 feet tall) and therefore show up better in the landscape.
They have pink flower heads, rather than the dull white of boneset.
But not all gardeners grow boneset for ornamental reasons. Gardeners interested in traditional herbal remedies may grow boneset for its medicinal properties. It has been used to treat fever, flu, and the common cold, among other ailments. In fact, the botanical name of "Eupatorium" derives from the name of a king of a country in the ancient world (Pontus) who is supposed to have discovered the medicinal properties of boneset: Mithridates VI Eupator (132 to 63 B.C).