I received an email requesting more info on how to cut back California poppies (Eschscholzia californica) so that they bloom again. This is what my poppies do through the bloom period and how I handle it.
After poppies have bloomed for a while their stems become very elongated and the leaves and stems turn powdery and grayish. I don’t think this is mildew because it happens even when there is no additional water.
Anyway, at this time there are usually flowers and ripe seed pods. You can tell the seed pods are ripes because they turn brown and grooves form lengthwise along the pod.
One of the grooves will become darker. If you open the pods, the mature seeds will be dark brown while immature seeds are green.
On a warm day when the seeds are rip the pods pop open spewing the seeds around. The spontaneous opening of seed pods is called dehiscence. When they pop open it is described as explosive dehiscence because it doesn’t just gently open, it actually pops propelling the seeds so they cover a larger area. I harvest the seeds when I see the grooves, placing them in a paper bag. Over time the pods pop and are collected in the bag. If you do this, make sure the bag stays dry and check it often for insects (notice the earwig chowing down on my seeds!).
Now back to cutting the plants back. Poppies are actually short-lived perennials. The same plant can live for a few years, though since they reseed so easily it is hard to keep track of who is who. Once they have bloomed, turned gray, and developed mature seed pods, I cut them nearly to the ground. I have a lot of poppies so I do this quickly and carelessly. In fact a weed whip or lawn mower with the blade set high would work.
You can tell this will work because the plant often sends out new leaves near the base of old stems.
I harvest the seed pods and compost the plant.
Here’s a group of poppies that are ready to be cut back. Even though they are still blooming the foliage is gray and seed pods are maturing.
Sometimes I cut them back more harshly than this, but either way works.
Here’s the pile of foliage that I throw into the compost pile after collecting the nearly ripe seed pods.
Below is a plant that was cut back a few weeks ago. The foliage is green but you can see old stems among the new growth.
And finally here is a poppy that is blooming again. Usually they don’t bloom as profusely later in the summer and often the flowers are smaller.
If anyone does it differently or has something to add, please comment.