Sometimes, fortunately not too often, we get feedback of plant failure after they have been planted out. Whenever we hear such cases we like to try and work out the reasons.

In some cases it can be impossible to know the reason. It can be expected that for every 100 plants planted out, not everyone will survive. A natural mortality rate of 1-2% should be expected.

When the mortality percentage gets higher though, a problem should be assumed to exist. If the problem is not identified, then it can be expected replanting with replacement stock could lead to the same result.

The number one reason for failure (by far) is ignorance and people trying too hard. Some customers literally love their plants to death.

To give some examples:

1. A customer purchases 100 azalea plants and plants them out. Some time later they return to us and complain they all died - implying we did something wrong. "Did you give them some water?" I asked. Yes they gave them some water "Did you damage them with a weed eater?" I asked. No they did not use a weed eater. "Did you give them a feed - meaning did you give them some fertiliser?" I asked. Yes they gave them a feed. "How much did you give them?" I asked. A handful per plant came they reply. "Of what?" I asked. Ammonium nitrate came the reply. "How did you apply it?" I asked. A handful on top of each plant they replied.

Needless to say they were somewhat distressed to be informed they blew their plants to bit with rocket fuel. That if such fertilizer is to be used, only half a tea spoon per plant, and only scattered on the soil surface. That many of these super concentrated fertilizers become acidic and toxic when applied excessively and it becomes wet.

2. A customer purchases some 200 lavander plants for a border. Sometime later they return and complain most had died and the few that remained looked terrible.

Again the same sort of questioning routine was carried out. "Did you give them a drink?" I asked. Yes they were given water. "How was the water given?" I asked. Oh we have an in situ irrigation scheme in the garden came the reply. We turn it on at 7 in the evening and turn it off at 7 in the morning.

Need more be said. They turned their garden into a swamp - for lavander - many of which originate in a hot mediterranean area.

Other stories abound, from livestock eating plants, dogs weeing on them, cats sleeping on them, weed eaters wacking them, chainsaws, lawnmowers, over planting, planting too deep, planting them but not removing the container they were purchased in, planting in rock hard clay, drowning them to death, fertilizing them to toxicity, and unloading them from a truck by lifting the hoist up. Yes it has all happened. And most of it can be summed up as silliness.

In a few cases something might be wrong with the planting site. Has the site been historically contaiminated with something - diesel or oil spillage, chemicals, tanalised sawdust.

Tanalised sawdust should never been used. It is my understanding the tanalith treatment used to preserve sawn timber contains arsenic as a chemical ingredient. (Not sure now, but it may be arsenic is no longer used in treating timber.) Why would anyone want to spread arsenic around their property. (For the same reason tanalised timber should not be burnt - why do we want arsenic being dispersed by smoke?)

Even natural untreated sawdust can cause problems, because as it breaks down the composting process tends to burn the nutrients out of the top soil, and plants can turn yellow from nutrient deficiency, especially nitrogen and iron deficiency.

Grass clippings are one of the worse things you can put around plants - yet many do. Ask any professor of soil science, and they will tell you as grass clippings decompose they seem to contain every pest and disease known to plants.

If such material is to be used the best is sawdust, pea straw or similar that has been used in an animal envirnonment, the best being a piggery. The sawdust would be partially composted, and loaded with rich manure.

If choocky poo, horse manure or sheep pallets is used, mix it up with top soil.

Returning to the topic of this page, another set of factors which can adversely affect plants is pests and disease. Some plants are more susceptible than others. One of the big problems throughout the Waikato is grass grub, or rather grass grub larvae in the top soil. Grass grub larvae do not stop at eating the young roots of pasture grass. Rather they tend to munch on practically anything that comes their way. They act like a subterranean swarm of locusts, countless millions of them everywhere, yet most people are blisfully unaware of their existence.

If you think your nice new plants have been wrecked by grass grub do an autopsy. Check the base of the stem just below ground level and see if the stem has been ring barked. Check the soil around the roots - can the larvae be found. (About 5-10mm long like a off-white colored maggot.) Another sign is if the filament roots of a plant are brown, mushy and rotten, when they should be white and robust.

Grass grub is easily controlled but only using chemicals. A farmer would boom spray with something like fenitrothion, or use granules like Diazinon. For the home gardener, less potent means are now available, including pyrethium based granular insecticides which can be applied to the soil surface like salt and pepper.

Another reason for failure is the wrong plant in the wrong place. Many plants are frost tender at a young age, including (believe it or not) many of the New Zealand native trees, especially those that are found naturally in a coastal environment. Vaireya Rhododendrons might look great around Tauranga, but I have my doubts about using them around Hamilton.

Of course, the last possibility for plant failure is that there may haven been someting wrong with the plant when we sold it and it went out the gate. It may be the problem was unknown and unnoticeable at the time and only showed up some time later. It has happened. So if you think this may apply to something that has died in your garden, dig it up and bring it back in to us so we can examine it. We will attempt to set you right. But if it died 12 months after being planted, I think it really is nothing to do with us.