With buxus blight cutting a swathe through many gardens, it is clear the problem is here to stay. We set out to review some of the alternative plant options. The advantages of box for low hedging include:
• only needs to be trimmed once or possibly twice a year
• has a very small leaf which means that trimming with hedge clippers doesn’t leave unsightly half leaves visible
• good dark green colour
• sprouts from bare wood if trimmed hard
• so easy to root from cutting that it is cheap to buy and easy for the home gardener to propagate more plants
• will also tolerate a certain amount of shade
We have yet to find a proven like-for-like replacement, only plants that fit some of the criteria.
1) Lonicera nitida – ticks all the right boxes bar one, but that is an important one. Good dark colour, tiny leaves, easy to propagate, cheap… but it grows so rapidly that you will have to clip frequently. This may be as much as once a month in the growing season. It will get very twiggy and leggy if you don’t keep it tightly clipped. The same goes for teucrium which needs even more clipping and isn’t even green, though it does make an attractive hedge.
2) Myrtus ugni, usually referred to as the NZ cranberry. Little leaves, easy to strike from cutting, easy to train and can be kept low, delicious fruit but it develops bare patches. It is really only an option for the edible garden area and it won’t make a nice tidy little hedge that resembles buxus. It doesn’t like shade and can be thrip-prone.
3) Gumpo or Kurume azaleas – these are the small leafed, low growing, evergreen azaleas. Good foliage, clip well, can be kept small though the leaves are larger than buxus and they have excellent shade tolerance. They flower, which some gardeners may not want. Gumpos tend to have larger flowers than the Kurumes. The big disadvantages are the expense per plant which will be prohibitive for many gardeners and the difficulty in sourcing large enough runs of the same variety. Some will get thrip (particularly the Gumpo types) so choose the variety with care. Evergreen azaleas are much easier to strike from cutting than most rhododendrons so keen home gardeners with a long term view, may want to try building them up at home.
4) Camellias – some of the slow growing, small leafed varieties are suitable though the leaves will still be larger than buxus. They trim well, resprout from bare wood and are a good colour. There is a limited number suitable for keeping down to a metre, let alone 30cm, so varietal selection is important. Camellias are not easy to root from cutting for the home gardener and can be expensive to buy. Microphylla and brevistyla set seed freely so could be raised from seed at home if you can find a parent plant. Itty Bit is a true miniature for low hedges. Night Rider is very slow growing, though ultimately larger in size. You could keep it to a metre but it will be expensive to buy. We have opted to go the camellia route in the event of our moderate metreage of buxus hedging getting blighted and have raised seedlings of C. microphylla in the nursery for replacement.
5) Euonymus – there are assorted selections of small leafed euonymus being hailed as buxus replacements, including one named Emerald Gem. These look promising but international reports are that euonymus are somewhat disease prone and local reports are that it can be thrip-prone which will rule it out for shady areas. We would recommend trying this as hedging in a modest way before getting too carried away and we have yet to be convinced of its long term merit. It should be relatively easy to root cuttings and is sometimes available in a hedging grade at a reasonable price.
6) Our friend Tony is sold on Melicytus obovatus, a native from northwest Nelson which takes clipping very well. In the wild it will grow to 2 or 3 metres (but common buxus can become a huge shrub resembling a small tree left unclipped). Plantsman Terry Hatch at Joy Plants is very keen on this melicytus and produces it for sale. As far as we know, it has yet to be tested in the long term (by which we mean as a garden hedge past a decade) but it is worth a close look.
7) Selected pittosporums will make good taller hedges but you are fighting nature to keep them to the low level of edging buxus. Their leaves are also correspondingly larger. The compact pittosporums, Golf Ball and similar selections, make a quick option for clipping balls and topiary, if you don’t mind the paler shade of green. Keep them in full sun with plenty of air movement too.
8) Corokia will make a good hedge and there are dwarf selections available but they are harder to trim if the new growth is left to harden. If not cared for, they can develop bare patches.
9) Twining Valley Nurseries in Pokeno are producing Ilex crenata ‘Helleri’ as a buxus sub. Ilex are the holly family and crenata is a small leafed species from Japan and Korea. It is recognised as a good hedging plant but I have only seen it in photographs and I don’t know how low it can be kept. It is worth investigating.
10) Our native alpine totara, Podocarpus nivalis, stays very low and can be clipped hard to get dense foliage. However, it is a long term option, it will be expensive to buy in quantity and it does not have the good green of buxus.
We have yet to hear of low hedges which have stood the test of time – by which we mean 10 years, not one year. Until there are more reliable reports, we would not advocate spending too much money and effort on major plantings of alternatives. There simply are no easy answers for a replacement for buxus and we keep coming back to the view that it may be timely to review the role of low hedges in New Zealand garden design.
For earlier articles on the topic of buxus blight and the role of buxus in a garden situation, check out:
* The appropriately named buxus blight
* There is life beyond buxus hedging
* Trouble with buxus
* DEBBO (that is: death by bloody buxus overload)