My new Chinese fir is just a little thing, but Cunninghamia can grow 2-3 feet per year. Staked as it is, this one was likely propagated from a side branch. With most conifers, this would mean that it would never grow like a normal tree, but rather remain low and shrubby. This trunk will do exactly that, but Cunninghamia have the ability, indeed propensity, to produce new upright trunks from the base. In fact, there is already a tiny new shoot at the base of mine that will likely grow into a normal, upright trunk, provided the leader is not removed.
I now have a piece of evolutionary and agricultural history in this Cunninghamia. I plan to untie the shoot from its stake, which will encourage new, upright trunks to develop at the base. Branches that touch the ground can also root and produce upright trunks. If left to its own devices, these trees can produce entire groves from a single plant. Most people would probably prefer to control it by removing the lower branches so that they can't root and removing suckers arising from the base of the trunk. I've seen a mature specimen allowed to sucker and root along the branches and I love the primeval look of a grove of Cunninghamia permitted to grow uninhibited, so I'll be letting it do whatever it wants.
The old branchlets and needles persist for several years and can create a messy look of dead, brown bits inside the tree, as well as dropping to form an enduring mulch on the ground. Personally, I don't mind the brown bits and will welcome the self-mulching feature.
The stats on Cunninghamia lanceolata 'Glauca':
- Hardy in USDA zones 7-9, grows in zone 6 but suffers winter die-back and requires more frequent cleaning of the persistent dead, brown needles and branchlets
- 35-70 feet tall, depending on environmental conditions, width depends on number of trunks allowed to grow, may exceed 25 feet
- It is generally said to prefer average to moist, rich, acidic soils in open shade with protection from strong, drying winds.
- It actually tolerates some of the most grueling conditions of drought, clay soil, low fertility and full sun
- Main ornamental feature is the blue color of the glaucous needles, which can be over 2 inches long
- Similar to a monkey puzzle tree in youth, but with a looser, more feathery appearance and may become very dense with age, always somewhat wild and ragged
- May take on bronze tones in cold winters
- Mature trees have brown bark that exfoliates in long strips, revealing reddish inner bark
- No serious pests or diseases. Stiff, sharp needles make it unpalatable to deer
I quite like the blue of the Cunninghamia against the bronze new growth of Rhododendron 'Gartendirektor Glocker'. I may have to come up with a way to implement this color combo, though planting the rhododendron with the Cunninghamia at this stage would require moving the rhody further out as the Cunninghamia expands, not to mention getting enough of the rhody to make a mass of them so as not to get lost against the mass of a mature Cunninghamia. Perhaps a tree with burgundy foliage planted nearby will be in order. I can see a Cercis canadensis 'Forest Pansy', purple smokebush, or even a taller red Japanese maple contrasting nicely with the blue needles. The wheels are spinning. That's always a dangerous sign.
Speaking of danger, My favorite plant in the garden this week is hosted by Loree of Danger Garden. Be sure to check out her blog to see what captured her interest this week and the comments below to see what other garden bloggers have been geeking over.