Many of my favorite dwarf conifers were first discovered as witches’ brooms growing high in the branches of their parent trees.
“Witches’ brooms? What are you talking about, Ed?” You may ask.
I’m glad you asked! Horticulturally speaking, witches’ brooms are tightly congested formations of twigs and foliage that are often, but certainly not always, caused by pathogens – insects or other biological pests. Sometimes though, a witches’ broom develops because of a genetic mutation. When cuttings are taken from these genetic abnormalities, new plants can be propagated with the characteristics of the mutated original.
“Yes, Ed, that’s all well and good, but why use the term witches’ brooms? Where did that originate?”
Great question. According to an article I found in volume 27 numbers 4-5 of Arnoldia, a bulletin of the Arnold Arboretum, the term originated back in medieval Europe. The genetic or pathogen influenced growth looked a lot like the rustic brooms that were in common use. And hey, if they couldn’t explain it, there must have been a witch involved! Not only that, but apparently, these congested foliage areas were the Motel 6 of medieval witches because they were thought to be the resting places of witches when traveling!
These days, dedicated conifer collectors are always keeping an eye out for witches’ brooms in the trees overhead for the potential of discovering what may be a really great new dwarf conifer for the garden!
One such conifer was discovered by Don Shadow. In 1984, he gave Jean Iseli some cuttings of his new discovery and these cuttings were grafted and evaluated for several years. Picea orientalis ‘Shadow’s Broom’ is a great plant with its bright spring-green new growth that quickly matures to one of the darkest and richest greens in the garden. It has short, glossy needles and slowly forms a broad mounding specimen. I’ve been growing mine in full sun where I needed a good dark foundation to my garden. It really stands out nicely surrounded by other more brightly colored dwarf conifers and other exciting garden plants.
Thanks to my friends at Iseli Nursery for the photo link