Category Archives: Garden lore

Wisdom and hints

Garden Lore – when renga renga lilies go bad.

img_3017Our native renga renga lilies are an immensely handy, low maintenance plant for semi shade. However Arthropodium, most commonly A. cirratum, can run into problems. This is particularly evident this spring which may have something to do with the dreary, cool and wet conditions. I saw it out and about while garden visiting around the region last week, most commonly in well established clumps. The unsightly spotting and markings on the foliage looks as if it is a rust but apparently it is not.

I repeat the advice given back in 2010 from a most reliable source, though regrettably these days, it should refer to “the late George Fuller”.

“Esteemed colleague, George Fuller, tells us that it is not a rust that causes orange blotching on renga renga lilies (arthropodium) but in fact a nematode (or wire worm). These critters can build up in a patch over time so if it worries you, it may be necessary to resort to using a systemic insecticide. A systemic insecticide is one that the plant absorbs as opposed to contact insecticides which only kill with a direct hit. The nematode is actually in the plant and it is the same one that attacks chrysanthemums and black currants, answering to the name of afelenchoides ritzemabosi.”

I did a quick net search to see if this is still current advice but after looking a plethora of sites that declare renga rengas to be largely free of pests and diseases, I figured that they hadn’t seen the afflicted plants in Taranaki this year.

Updating for 2016, we are hesitant these days to recommend the routine application of heavy duty systemic insecticide. We don’t know whether a one-off spray will clean up the plants in a single hit or whether repeat applications, maybe even on an ongoing basis, are required. The alternative courses of action are never quite as straightforward of course.

img_6240Because the nematode apparently lives in the leaf, not the soil, it seems unlikely that badly infested plants will grow out of it on their own accord. Firstly, look at the infected plants and note whether they are the oldest, best established clumps in your garden. Also take stock of any plants showing clean foliage or very little damage. Our course would be dig out and dump the worst affected plants. Clean up and dig over the ground and either replant with clean renga renga lilies or an alternative. If you have clean plants in your garden, these can be lifted and divided. It may be that they are not showing damage because they have developed some resistance. Given optimum growing conditions and increased air movement, the plants are likely to respond with vigorous new growth. If you only have a few affected leaves, then cut them off but you can only compost them if you make compost that is hot enough to kill bugs and diseases. Otherwise, you are going to have to remove the foliage well away from the site to prevent re-infecting your new plants.

Whether you take the quick and dirty course of using a spray or the longer and more environmentally friendly course is entirely your choice. If you have a bad infestation, it is likely you will want to do one or the other because the plants can look pretty awful as they are.

Garden Lore – slugs, snails and baits

“Not all slugs cause damage to your garden. The great grey slug is relatively harmless to your precious vegetables and flowers because it generally eats fungi and rotted vegetable matter and even its other, less welcome cousins. The European black slug has as many as 25,000 teeth. Although it will eat your prized plants, it serves a more welcoming purpose by devouring dog and cat poo and turning it into fertilizer.”

The Curious Gardener’s Almanac by Niall Edworthy (2006).

I do not know if we have the great grey slug in New Zealand, maybe not – though it sounds similar to the large tiger slug that we have a-plenty.

Slug bait is not fertiliser

Slug bait is not fertiliser

While out and about garden visiting this week, I came across this little scene. I photographed it for Mark in the first instance because he has long railed against the practice of using slug bait like fertiliser. But it is a good example and time to remind readers again – slug baits have an attractant in them so you do not need to lay entire carpets of bait in the hope that slugs and snails will trip over one.

It is a poison and will find its way into the food chain so do not be lulled into a false sense of security when the packet tells you it is safe for animals and birds. It also needs to be reapplied after rain. Rather than shaking the box to scatter pellets, keep a pair of disposable gloves with the slug bait box. Tip some pellets in one hand and place 2 or 3 pellets by affected plants (Mark would tell you that a single bait is all you need). Cheaper, more environmentally friendly, better for the birds and more pleasing aesthetically.

Or try little bait stations in badly affected areas – a milk bottle lid filled with a few baits and a cover to keep it dry. We use old paua shells. Note: just three baits to this bait station.


Garden lore: chainsaw pruning

“There appears to be a large element of tree worship in us Americans, and anything remotely connected with a tree is approached with a numinous awe. People who are slothful by nature and who never get around to cutting down the peony and lily stalks in November (though this is well worth the labor) and who never divide irises on time, or plant the daffodil bulbs before Thanksgiving, or prune the climbing roses – such persons nevertheless leap into action when leaves fall, as if the fate of the garden depended on raking them immediately. I do not intend to comment on that situation, on the grounds that fiddling with leaves is no more harmful than cocktail parties, marijuana, stock car racing, and other little bees that people get in their bonnets.”

Henry Mitchell, The Essential Earthman (1981).

Camellias severed to bare stumps 6 months ago

Camellias severed to bare stumps 6 months ago

Times have certainly changed since Mitchell wrote the above para. The modest rake is more likely to be a noisy leaf blower these days. Loosely related, I thought some readers may be interested to see the after effects of extreme winter pruning.

Both the michelias and camellias were four to five metres high, stretched and thin as they reached for the light. Because we are making a new garden and have opened the area to the light, we wanted a hedge effect, not a straggly, willowy shelter belt. In winter last year, these plants were taken to with a chainsaw. They were cut off at about a metre in height, in many cases leaving no foliage at all.

Well established michelia hybrids respond to hard pruning with abundant fresh growth

Well established michelia hybrids respond to hard pruning with abundant fresh growth

After about six months and a spring flush, the new growth is phenomenal. We won’t get any flowers this year but we will have a bushy, well established hedge sooner, rather than later.

This extreme action does not work with all shrubs but it can be done with camellias and michelias. It may not work in harsher climates, either, but in our mild, temperate conditions it is fine. The timing is relatively important. It needs to be done well before the spring flush and we find early winter is the best season. It is a hedging technique. The trade off is that you lose the shape of the plant but gain bushy growth instead.

Garden lore – three hedging ideas for 2015

“My garden sweet, enclosed with walles strong,

Embanked with benches to sytt and take my rest:

The knots so enknotted, it cannot be exprest,

With arbors and alyes so pleasant and so dulce.”

George Cavendish (1499 – 1561).


How to punctuate the end of hedge with panache and style in 2015.

I was taken to see the gardens at The Kelliher Estate on Puketutu Island in Auckland last week. When we say island, it is connected by a causeway. No ferry crossings were required. The gardens have been undergoing a major renovation in the last few years. There is a difference between a restoration and a renovation. The former attempts to recreate the gardens as they were in their glory days. In our climate with rampant growth and a heavy dependence of woody trees and shrubs, restorations are somewhat ill-conceived, in my opinion.

Renovations are a reinterpretation of a garden and in public gardens can range from pedestrian to insensitive, from ego-driven (the modern gardener determined to ‘make his or her mark’) to compromise by committee. Occasionally they are carried out with genuinely creative flair and there were indubitably elements of this showing in the gardens at the Kelliher Estate.


I was simply delighted by the reworking of the formerly overgrown lilly pilly hedge at the entrance – cloud pruned. With panache. I am no expert on lilly pilly. In fact it is more akin a yawning gap in my knowledge, especially as there are a number of plants which carry this common name. But I am guessing that this particular lilly pilly was the Australian myrtle also known as Syzygium smithii syn Acmena smithii (see footnote). If you are going to try something like this at home, take your time. You can’t rush the process of finding the natural shape of each individual plant. And trim flush to the stem. Nothing looks worse than nubbly elbows poking out all over the place where you have lopped off branches.


Finally the wave hedging is a device I have seen in UK and Europe but not in this country before. It echoes the natural shapes of the landscape but gives some form without the regimented and straitjacketed predictability of the usual flat topped, formal hedge.

The one key element to remember if you decide to get more adventurous with your own hedges is to ensure that they will tolerate hard pruning and resprout from bare wood if you are going to reshape. Not all hedging plants do and conifers can be particularly touchy.

Postscript: Social media can be very helpful. The following more knowledgeable comment on lilly pillies was made on the garden Facebook page by Andrew from Twining Valley Nurseries
“You’re not wrong with the naming of Lilly Pilly. I’ve been to garden centres and seen the same plant labeled with three different names!
The correct taxonomic names for the 3 most commonly grown Lilly Pilly’s in NZ are-

Waterhousia floribunda (Old name: Eugenia ventenatti or Syzygium floribundum) Common name: weeping Lilly Pilly
Syzygium australe (Old name: Eugenia australis) Common name: brush cherry or Australian rose apple and is the most common.
Acmena smithii (Old name: Eugenia smithii) Common name: Lilly Pilly (or weed!)”

Thanks Andrew.

Garden Lore: “Touch the earth lightly”

“Touch the earth lightly, Use the earth gently
Nourish the life of the world in our care
Gift of great wonder, ours to surrender
Trust for the children tomorrow will bear.”

Verse 1 from the hymn “Touch the Earth Lightly” by Colin Gibson and Shirley Erena Murray (1991).
Photo0084 - Copy
Photo0072 - CopyReally it is the first line I like – “touch the earth lightly, use the earth gently” but I added the rest of the verse to give it context.

We went to a funeral this week which we do not often do, I admit. But in this case we both wanted to honour the late George Fuller. George was probably best known in this area as long standing curator of our main central city gardens, Pukekura Park, and as a defender of trees. In this role, he was more successful than we have been recently. His personal passion and his international reputation was in the field of orchids – hence the orchid display at his funeral.

To die at the age of 86, surrounded by a large, loving family and to leave behind a worthwhile legacy is to be celebrated. The selection of the hymn seemed particularly apt for such a gentle, humble man.

What a wonderful epitaph, or indeed a principle to live by – touch the earth lightly, use the earth gently.