Gardenocracy

Helictotrichon sempervirens looking unhappy at the end of summer

It’s the time of the year when I wander around the nursery assessing how well plants have handled the summer and whether they should be promoted, given another chance, or demoted to the scrap heap. This year has been better than most for testing a plants mettle, with daytime temperatures almost continuously above 30℃ from January through March.

This Helictotrichon sempervirens (Blue oat grass) is one of those plants on it’s last chance. Considered by many gardeners the finest blue grass of all it should be spectacular and coming from the Mediterranean I expected it to do well. After failing with it in pots I finally got it in the ground where it would not receive too much water but more than enough to keep a supposedly drought tolerant plant happy. It looks pretty much the same at the end of this summer as it has at the end of every other. Being a winter grower I will give it until spring, then if it still doesn’t show any promise, or at least look like it might flower, I’ll replace it with a more reliable blue grass, another Schizachyrium scoparium (Little bluestem) or a Sorghastrum nutans (Indiangrass) that’s been begging me to get in the ground.
Among other plants that will be getting the chop this year are most of the English hybrid penstemons, with the exception of ‘Alice Hindley’ and ‘Pink Dragon’ they just can’t handle the heat, a pity because they are so beautiful and flower their heads off. No loss, they will be superseded with wild North American penstemons, like Penstemon palmeri, Penstemon eatonii and Penstemon heterophyllus that seem to quite revel in the heat and are far more resistant or even demanding of dry conditions.
Adenophora nikoensis a Campanula relative has also failed to impress. Having enjoyed the pale lavender bells of Adenophora triphylla for many years I thought I would try another species but since growing them from seed in 2008 they have made meagre growth in spring only to fizzle as the temperature rises. They are from woodlands somewhere in the mountains of Japan so I’m not really surprised at my lack of success, though other Japanese natives do well enough. They can now find homes in the gardens of gardeners in cooler regions who are eager to try them.
A couple of plants that unexpectedly passed summer’s test with flying colours are Scutellaria alpina and Edraianthus graminifolius, considered alpines they have both come through unscathed and look set for a stellar flowering come spring.