Friday, May 11, 2012

The fat culms of May

It's that time of year when bamboos are starting to push out the current year's growth.  The first sign is the emergence of fat culms from the rhizomatous root mass.  This was Chusquea coleou this morning.

New culms of Chusquea coleou
They are just over an inch / 2.5cm thick at the base, the thickness they will retain as the canes rapidly grow to about 10-12ft / 3-4metres tall over the next few months.  Of course, by bamboo standards this is nothing exceptional.  Even in the UK some of the stronger growing species can reach heights of 30-40ft / 9-12metres inside a single growing season, fuelled by the nutrients packed in their root systems from the previous years growth.

I like Chusquea coleou.  It retains its tightly clumping habit into maturity.  Mine has been in the ground since 2006 and occupies a footprint of about 6 x 6ft / 180 x 180cm.  I thin a few of the older canes every year but, other than the normal garden feed in spring, gets no particular attention.  The result is this:

Chusquea coleou
It's not the only bamboo I grow.  Phyllostachys nigra, the black stemmed bamboo, grows against my east facing garden wall.  This has also remained fairly compact but needs more attention.  The black canes cry out for the lower shoots to be removed to enhance the display.  In late autumn, as part of my garden tidy up, I spend time trimming the side shoots on new canes.  I aim to leave a clear stem of about 5ft / 150cm.  At this stage the new canes are green.  They will darken over the next year or so to the ebony darkness that adds so much to the attractiveness of this popular bamboo.

Phyllostachys nigra
This treatment is not a necessity with Pleioblastus auricomus.  A yearly winter haircut to remove the previous years stems is all that is required for this dwarf bamboo.  I've recently moved and divided mine and the small section I've retained is recovering nicely to provide upright yellow contrast in the garden.  It will make about 5 - 6ft / 150 - 180cm once it's re-established but, on the evidence of the past fifteen years, stay tightly clumping to create an attractive garden feature.

Young growth on Pleioblastus auricomus
I wish I could say the same about another bamboo I grow.  x Hibanobambusa tranquillans 'Shiroshima' (try saying that after you've had a drink!) is a variegated form of a natural hybrid between a Sasa and Phyllostachys.  It is reliable in retaining bright variegation throughout the year, producing 8ft / 240cm canes with me, but what it isn't is a nice tight clumper.  It's often described in these terms but believe me it's not.  OK, it's not as invasive as the Sasa parent but it happily runs around in my top border in the front garden.  There are a lot of big plants in there to keep it under control so its not a real problem - but canes pop up in random locations along 10ft / 3metres of the border.  Mind you, it is pretty.

x Hibanobambusa tranquillans 'Shiroshima'
One bamboo I regret losing was Fargesia nitida 'Nyphenburg'.  It formed a graceful feature in the garden for a good few years.  Then, in 2008, I noticed it was flowering.  Bamboos do - they are only big grasses after all - but they do it irregularly and in synchrony with all other members of the same species.  After flowering death usually follows - and this was certainly the case with mine.  It lingered till 2010 but it is most definitely an ex bamboo by now.  I've cut down but have still to remove the remains - a project I'm putting off till I refurbish that area of the front garden - so the stumps sit in mute reminder of what once was.

Fargesia nitida 'Nymphenburg'
I'll replace it in due course but, in the meantime, I've just added another bamboo to my small collection.  Phyllostachys aurea 'Aureosulcata', a golden caned bamboo, destined for a spot behind the tree fern in the 'pool' garden to provide some much needed shade.  It's only a baby - the budget won't stretch to large plants - but should fill in over the next two or three years to provide elegant height at the end of the rear garden.  I've heard reasonable reports of its generally non running nature but, just in case, it will be confined in a block edged space to prevent any wayward rhizomes escaping into the rest of the garden.

For elegant height in even small gardens there are few plants as suitable as bamboos.  Some can be as wildly invasive as Attila the Hun but there are many that are restrained in habit or relatively easily controlled.  Many more than I have the room for, unfortunately.  But I'm happy with what I've got.  Although I can get an offshoot of the very jungle like Sasa palmata 'Nebulosa' from a plot holder on my allotment.  And I'm sure it would be fine in a large container in my little front courtyard.  Wouldn't it?

1 comment:

  1. Nice selection of bamboos you have there John. I echo your thoughts on Chusquea culeou, it is a lovely bamboo. I think the Sasa palmata will be fine for awhile in a large container, that's how I keep mine. It is very invasive to be planted out (even if it looks behaved for its first few years), perhaps in the future if we ever have acres of space.