Tuesday, May 22, 2012 | | Agastache, Aster 'Lady in Black', greenhouse, How, When, What-we-do, North Garden, perennials, pinching plants, propagation, tip cuttings
Despite knowing that pinching new growth makes plants branch into full and sturdy clumps that promise extra flowers, it can be one of the hardest things to do. Somehow it goes against the grain to nip healthy new growth and I just can’t do it sometimes. But then I always wish I had. The nepeta at my house grew so fast I missed my chance to pinch them before the flowers budded and now they’re splayed open and not-so-very pretty even though they’re blooming away. If only I had pinched them back in … April. Or if not in April, then a couple of weeks ago when I realized they were about to bloom. It would have been better to set the bloom timing back a bit for the sake of sturdier, bushier growth. Mental note for mental toughness next year.
Last year our Agastache ‘Black Adder’ and ‘Blue Fortune’ were tall and a little rangy so we determined to remember to pinch them this year. They should end up being a little shorter, the blooms might not be quite as large possibly, but the plant will look much better in the garden and there will be even more flowers for the bees.
We also pinched Aster ‘Lady in Black’, which we bought as spindly single-stemmed plugs. Cutting off the apical meristem, the tip of a new shoot, will send energy into the side shoots and make the plant branch. It feels barbaric to lop off their heads but they almost instantly respond – within a few days anyhow – by starting to branch out from every axil. I hate to think how weak and unattractive the plants might be if we didn’t decapitate them.
And the consolation prize for following through with this necessary but weirdly difficult task is that the pinched tips of annuals and perennials make the best cuttings – as long as they’re not blooming yet. Spring cuttings take much more quickly than fall ones – fast enough that we should have more plants to tuck in later where we need them.
Make sure the cuttings are neither floppy nor woody. Trim off the second or third set of leaves from the top right at the stem using a sharp knife or razor blade. Trim the remaining leaves in half, dip the end of the stem in rooting hormone, and stick it in dampened sterile rooting medium like perlite or vermiculite. If you don’t have a high-tech mist system like we do, put a low-tech clear plastic bag over the cuttings and mist them with a spray bottle occasionally. Keep them in a bright warm spot out of the sun and they should root in 2-4 weeks. Pot them up for few weeks before planting them out.
Other plants on our pinch-now list are the ones that bloom late in the season like chrysanthemum, which can be pinched again around Father’s Day; Boltonia – I swore last year that I would pinch ‘Nallie’s Lime Dot’, and Helianthus – ‘Lemon Queen’ to keep them from keeling over; and rabdosia (trumpet spur-flower). We also sometimes pinch summer phlox – but only if we don’t want them to get too tall (otherwise we’ll just thin out some stems to give them better airflow); dahlias if they’re up and leggy, Salvia, and potted annuals when we plant them even if they’ve already been pushed into bloom.
What plants are you pinching back now? Are you squeemish about doing it too?