One of our customers requested assistance from us. She had purchased a number of 100 litre Syzygium leuhmannii and most were doing better than she anticipated. However, she was not able to understand why four were not growing and had actually deteriorated. On inspection we discovered that these four were planted above a neighbour’s retaining wall that had a very good drainage system to protect the pressure on the wall and had a wide area of backfill with very porus material. Our customer could not see this because the top 750 mm was backfilled with ordinary top soil. When watering, this was done on the area where the porus fill was placed and of course no benefit went to the trees. On relocation of the watering system to benefit the trees all were saved and these trees progressed normally. Note:- Too much drainage can negate your watering efforts.

Swimming pools

The Lilly Pilly may be the best choice for around the swimming pool. Being a fast growing evergreen with non invasive roots and able to be cut and pruned to shape makes it the ideal plant. We would recommend the Syzygium luehmannii (Small Leaf Lilly Pilly). Any leaves that fall are very light and usually go straight to the skimmer box, however keep it back far enough so the fruit does not drop into the pool. When deciding on which plants you would like to place in the vicinity of the pool look at the plant index at the top of each group of plants and plant key descriptions for mature heights and widths. A general rule of thumb would be to keep the plant the same distance away from the pool as the mature width on this index.

Unexpected dose of salt

Quite a while ago a customer purchased a number of Syzygium leuhmannii. These were in a 100 litre bag size. He planted four in a row along the pool and five across the back fence for screening. They grew very well and he was very pleased. Then for no apparent reason, one of the trees along the pool side defoliated although it had received exactly the same treatment as the others. We went to investigate and could not understand what had happened. While we were looking at the trees, one of the owners’ children jumped into the pool. We then noticed that a very small river of water came over the catchment area and basically trickled down to the affected tree. We then discovered that it was a salt water pool and the salt had built up around the tree causing the defoliation. Even though Syzygium luehmannii are considered good for coastal planting, the salt concentration was too severe around the root ball.The owner swapped this tree for one from the back and adjusted the surface drainage to alleviate the problem. We believe a strong concentration of chlorinated pool water would have the same effect so check this in your own garden when planting near pools. A good hosing will usually dilute the effect of the salt or chlorine.

Thirsty or drowning

We had an altercation with a Council Foreman after we sold them some Cupaniopsis anacardioides (Tuckeroo). On delivery we discovered that they were pulling out dead ones and wanting to place our new trees into the same holes which were totally waterlogged. The existing holes had a 100 mm vertical water pipe placed right to the bottom of the hole but no drainage. We have observed at various times that people, when planting trees along footpaths, etc. place short lengths of 100 mm pipe vertically in beside the trees to water them by filling the pipes with water. This is better than no water at all, but by watering this way, you will run the risk of creating a well in poorly drained soil. This will in turn rot the roots and the tree will most likely die. Trees should be watered where the feeder roots are located and allowed to pass over the whole of the root ball, right out to the drip line.

Hillside hassles

We have been called to many gardens where trees, although having been planted on a slope still showed drainage problems. When planting a large tree on a slope it is advisable to dig a trench on the low side out from the bottom of the hole then re-fill loosely to keep excess water away from the roots.

Ringbarking with mulch

A customer called us after having already lost one tree in a row of ten Harpullia pendulas and it looked like he might lose another one. On inspection we found that the mulch on these two trees was pushed up against the bark and had effectively ringbarked the trees. Always keep any mulch back from the base of the trees and only to a depth of no more than 50mm out to the drip line.

Laziness can kill

A landscaper contacted us some years ago about a large tree he had purchased for a shopping centre project. The tree had deteriorated and he was unsure of the cause. We pulled the tree out using a rope tied from the tree to a ute. It only took one pull and the tree bounced out of the hole and just missed the gathered observers. The reason for the trees condition was then obvious. The root ball that was originally 750 mm in depth had been cut and reduced by 300 mm to 450 mm. It was discovered that the landscape labourers, when planting it, had decided that the ground was too hard to dig any deeper than 450 mm and had instead chopped the root ball to fit. Note:- The root ball should not be trimmed to fit the hole. Dig a bigger hole.

Bag removal

A customer purchased a Syzygium (Waterhousea) floribundum for screening purposes. This was in a 500 litre bag and was a beautiful tree. This tree was planted and an automatic watering system installed but the tree deteriorated. On the customer’s request we visited the site and we were dumbfounded. Everything appeared to have been done as outlined in our planting guide supplied with the tree. Unfortunately the tree could not be replaced as this was the last 500 litre Syzygium floribundum we had available for sale. We replaced it with a very mature 300 litre tree. We supplied the tree and the customer was to plant it. At this time we gave the customer a list of landscapers who would be able to plant the tree. He used one of our regular tree planters. On the changeover day while we were loading the 300 litre tree for delivery, the landscaper rang me and advised he had identified the cause of the problem.The bag had not been removed from the 500 litre tree and consequently the tree was not getting any of the water from the automatic watering system. The system was directing the water to the outside of the bag and away from the rootball. The water could obviously not penetrate the bag from the outside. After further discussions with the client we were advised that the builder had planted the tree without consulting our planting guide. This situation was settled between our client and his builder. Note:- When planting in ground, bags must be removed.

Planting Palms (Tall)

Palms are more interesting if planted on an angle or in clumps of two or more together on angles. They are moreattractive than “lamp posts”.

Invasive root systems

This is based on observation and experience. Often the closest tree to the problem is not necessarily the invasive one. Look further afield when checking for the problem. We have noted that the roots from a mature Ficus for instance, growing many metres away from the problem area, will be responsible in its search for a water source.

Underground invasion

Once we visited a garden where the owner had kept a fig tree pruned back to a small ball shape and was wondering why his sewerage system was still being blocked with roots. His assumption that the roots would be no bigger than the spread of the tree was incorrect. Some tree species with invasive roots can reach out up to 50 metres underground with no major top growth.

Beware of Ficus in pots (Topiaries)

Many people have various types of Ficus in pots as standards or shaped. Beware not to transplant these into gardens when they outgrow the pots. Ficus are VERY INVASIVE. They need to be planted well away from underground services or drainage.

Frost Effects

Even though some species are frost tender, once they have reached at least a 25 litre sized plant (i.e. greater than 1 metre out of the bag), they are much more resistant to the effects of frosts, as the foliage is often above the frost. As an added insurance for the species that are most susceptible a barrier of jute/shadecloth to 0.5 metre high around the plant will help. Plants in larger bags are frost hardy and no protection needs to be applied.