Purple or dark red selections of big bluestem seem to be more susceptible to leaf rust, which shows up as orange or rust colored blotches on the leaf blade and sheath, and turns brown with age. Red October, shown below has quite a lot of rust. This is not fatal and is somewhat hidden in the darker foliage of these cultivars. Leaf moisture contributes to rust, so keeping the foliage dry does help.
Apache Rose is a new mid-height switchgrass with soft rose flowers and green foliage, below right. On the left is Blue Fountain switchgrass which is a taller form, with showy white flowers amid the very blue, fairly wide foliage. Both of these look good as 1 year old plants (planted in fall 2015). One of the Blue Fountain has been slow to grow (front plant). There are 4 of each of these plants in the Grass Collection at the Minnesota Landscape Arboretum.
‘Cape Breeze’ switchgrass is much shorter than most cultivars, full of flowers here at the Minnesota Landscape Arboretum on July 26, 2016. It is about 30 inches in height, note the ‘Ruby Ribbons’ label to the left, and the ‘Cape Breeze’ label hidden in the foliage. There is a market and need for mid sized grasses that have good plant form. ‘Cape Breeze’ was discovered on Martha’s Vineyard, MA and is known for being a shorter plant.
Thyme and self-heal (Prunella) are starting to show up now amid a lot of white clover in the flowering or ‘bee lawn’ plots that were planted at the Minnesota Landscape Arboretum in 2015. Mowed at 4 inches, with not much of the fine fescue showing, these 5 treatments all have some clover. The scalped (mowed to almost nothing, 1″) prior to seeding plots show the most thyme and self-heal. For more information see Planting a Bee Friendly Lawn and Flowering Bee Lawns.
A new planting of ‘Blue Heaven’® little bluestem shows one very different plant….it’s purple! Looks great, but will it last? Will it be as healthy and vigorous? We can all watch this one…it’s in the front gatehouse bed at the Arboretum on the right as you leave the grounds….where we can watch it without getting out of the car! Color mutations like this may or may not last through the growing season. Grasses appear to change quickly in variegation, cells that have more chlorophyll (green colored) being stronger, and more vigorous can crowd out weaker cells that have other pigments, or less chlorophyll, as this purple plant likely has.
There is just no stopping vigorous rhizomatous grasses! Native bluejoint, Calamagrostis canadensis is a great native grass for wet, shady sites and has attractive buff flowers often found in Minnesota woods, prairie potholes, and along Lake Superior. We just had to get it in check here; show before and after cleanup. Bluejoint is the center plant, but had encroached two other kinds on each side. Faithful volunteers working in the collection are the best!
Cool, below 32F, temperatures recently damaged the new growth on the Minnesota Landscape Arboretum grass collection. Looking at Spodopogon in wonder at the discolored foliage…..then looked at the label and dah…know why the common name is Frost Grass! Yes, centers show some rodent damage and the older dead sections, but all the discolored foliage is frost damage. I expect it to grow out of this in a short amount of time. Miscanthus also showed similar damage, as did little bluestem.