Plant of the Month

Giant Coltsfoot

Petasites japonica var. giganteus

Location: Grid T2 west side of the pathway through the Hosta Walk

Giant Coltsfoot is one of the most dramatic plants in the Arboretum. The flower buds emerge from the ground as soon as the winter temperatures start to moderate, usually sometime in February. They look like little tennis balls poking through the ground, often with snow still around them. The leaves follow the flowers, and they grow amazingly fast.

Giant Coltsfoot, Petasitesjaponica var. giganteus 4-2-12. This form of Coltsfoot is native to Japan; so, it is planted in the Asian section along with a variegated form and a palmate form. All of these are strongly rhizomatous and can aggressively fill whatever space they are allowed. Our three forms seem to have reached a balance in their space and they have not moved outside the bed.

Giant Coltsfoot, Petasitesjaponica var. giganteus 4-19-12 (21/2 weeks after the upper photo!)

The Coltfoots prefer a protected shady, moist spot, and even given that location the Giant Coltsfoot starts to look kind of ragged by mid summer with the big leaves tearing from the wind. In the heat of summer, even with the soil quite wet the leaves will usually wilt to some extent in the heat of the day, then bounce back overnight.

April Projects

Winter looked like it was over early in March; so, the ugly orange snow fences and the warning signs that are supposed to deter winter sports enthusiasts were all taken down. Then, of course, it snowed heavily for the first few days of 'official' spring! The weather earlier in the month did allow me to get most of the ornamental grasses and perennials cut back and cleaned up; and, a lot of the routine pruning has been finished as well.



'Idaho Endurance' Giant Sequoia, one year old graft 4-19-12

Upcoming Events

Arboretum Associates Annual Plant Sale
Saturday, June 2, 2012
Latah County Ice Rink, Latah County Fairgrounds Moscow Idaho

Plant Sale List

Pink Masterwort, Astrantia major 'Rosea'. A new plant for the shade bed in the coming Arboretum Butterfly Garden, available at the plant sale