In sea­son

British plant tri­als will help gar­den­ers look­ing to re­place blight-prone box, says Neil Ross.

NZ Gardener - - Contents -

Neil Ross looks at al­ter­na­tives to box

Think­ing Out­side the Box is an at­tempt to in­spire gar­den­ers to move away from tra­di­tional box hedg­ing.

I’ll never for­give Pete Bragg for the time we were walk­ing home from school and he dealt me a well-aimed shove, send­ing me tum­bling through an old lady’s hedge. Per­formed ex­pertly, the clas­sic shoul­der shove can de­liver a se­ri­ously meaty blow. I was com­pletely taken un­awares and crashed un­cer­e­mo­ni­ously, like a top-heavy skit­tle, leav­ing a gap­ing hole in the man­i­cured leafage.

Had my hor­ti­cul­tural pas­sions been more de­vel­oped, I could have pointed out to the house owner how we were do­ing her a favour, rid­ding her of a good bit of dread­fully dull privet and pro­vid­ing an op­por­tu­nity to re­think and re­plant, but as it was, she yelled and headed to­wards me at a pace across the lawn, bran­dish­ing a laun­dry bas­ket. I leapt the hedge and ran.

A warmer wel­come awaited at a recent visit to Wis­ley, the flag­ship gar­den of Bri­tain’s Royal Hor­ti­cul­tural So­ci­ety (RHS). In the re­vamped walled gar­den, I was re­minded of this child­hood tum­ble as I in­spected a set of finely trimmed but flimsy hedges of sim­i­lar size to the one I had de­mol­ished all those years ago. Some would have made a per­fectly springy land­ing pad for a way­ward teenager – the likes of di­var­i­cat­ing muehlen­beckia, for ex­am­ple – while others, such as sev­eral trendy new berberis cul­ti­vars on show in rain­bow colours, would have put short shrift to any such tom­fool­ery with their wicked spines. This re­vamp of what was once an area devoted to im­mac­u­late and gar­ish bed­ding dis­plays is branded Think­ing Out­side the Box, and is an at­tempt to in­spire gar­den­ers to move away from tra­di­tional box hedg­ing to less dis­ease-prone al­ter­na­tives.

Box ( Buxus sem­per­virens) has densely tex­tured and small ever­green leaves that don’t look ragged after a trim. The growth rate is not too vig­or­ous ei­ther so you can, in cooler parts of the world, get away with a sin­gle trim in the year (al­though two is nor­mal). But there doesn’t seem to be a

coun­try in the world that has not suc­cumbed to the su­per-fast de­fo­li­at­ing box blight ( Cylin­dro­cla­dium bux­i­cola). And now – in Europe at least – there is another ex­otic in­vader, the box tree cater­pil­lar ( Cy­dal­ima per­spec­talis) set to cause even more woe to the world’s favourite hedg­ing plant.

Some gar­den­ers have turned to the dwarf holly Ilex cre­nata. It looks like box but is even slower grow­ing – and the RHS have found its per­for­mance patchy in the sandy soils at Wis­ley. Per­son­ally, I find it rather stiff and brit­tle too, so if you have bois­ter­ous kids or are just clumsy step­ping over it to prune the roses, branches can snap off. I was sur­prised there were no sar­co­cocca shrubs on show or dwarf euony­mus va­ri­eties on trial be­cause I’ve seen these make good lit­tle ever­green hedges, but it’s nice to see that, in their search for a springy and tough al­ter­na­tive, the RHS has turned to sev­eral Kiwi plants.

The range of moun­tain to­tara ¯ ( Podocar­pus cun­ning­hamii) cul­ti­vars that was on show was im­pres­sive, from ‘Coun­try Park Fire’ to ‘Young Rusty’ – so new I’m not cer­tain they have been re­leased in New Zealand yet! Many have in­ter­est­ing pur­ple or bronze win­ter fo­liage ef­fects and strik­ingly bright new growth in spring, and they cer­tainly take well to clip­ping. In ap­pear­ance, t¯otara looks more like yew than box but that can be no bad thing; it’s a mys­tery how sel­dom we see yew used for hedges.

One strength of box is the fact that it can be main­tained as a small hedge below knee height, so I think the choice of some medium-sized pit­tospo­rums and corokias by the RHS will prove a chal­lenge to keep so small in stature.

Black matipo ( Pit­tospo­rum tenuifolium) needs a lot of clip­ping to keep it tight and neat; that might be a real draw­back. We have some su­perb dwarf va­ri­eties al­ready, such as pur­ple ‘Tom Thumb’, green ‘Golf­ball’ and grey­ish ‘Humpty Dumpty’ named in 2006 by McKech­nie Nurs­eries in Al­bany. These would all make small, in­for­mal hedges but you might strug­gle to co­erce them into crisp geo­met­ric shapes. Corokias are sus­cep­ti­ble to wet soils and tend to have up­ward-thrust­ing fo­liage which is never amenable to be­ing clipped low, but the cul­ti­vars on show looked to be do­ing well – in these early stages, at least.

The de­sign is based on El­iz­a­bethan knot gar­dens with the hedge tops cut to look like the dif­fer­ent va­ri­eties are weav­ing un­der and over each other in a lat­tice ef­fect. Cu­ra­tor Matthew Pot­tage in­tends to keep the ex­per­i­ment dy­namic by edit­ing ev­ery few years; dig­ging out the un­der­per­form­ers and swop­ping them with new ideas.

The test of a hedge comes with time, when re­peated clip­ping, wear and tear, and plants flop­ping and shad­ing the sides take their toll. But full marks to the RHS for fac­ing this prob­lem with such en­thu­si­asm and flair – and fly­ing the flag for our amaz­ing flora at the same time.

Newspapers in English

Newspapers from New Zealand

© PressReader. All rights reserved.