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Treated Pine and Broms do not Mix!


- Compiled by Gerry Stansfield
- extracted from the March 2005 Journal

After speaking recently with a friend who was heartbroken by the damage done to her bromeliads after placing them in a newly built shadehouse made of treated pine. I wondered if there might also be others out there who needed to know about the problems associated with treated pine.

The following is a story by Elaine Jones of New South Wales, which appeared in the September/October 1992 issue of BROMELETTER. Vol. 30 No.5, and although it was written over 10 years ago, the problem still persists…

‘In June 1988 after several years living in rented houses In Sydney, we purchased a home in the suburb of Dundas. It was an old house needing renovation and after several months we started on the garden.

One of the requirements was a shadehouse for my bromeliads. As we were using treated pine in the landscaping we decided to use the same for a pergola-shadehouse. Knowing that bromeliads are copper sensitive, I checked with the supplier as to whether there was any risk of the salts leaching from the timber I was assured that problem only occurred if the wood was burned.

Everything went well for a few months until I noticed brown marks about the size of a one-cent coin at the base of some of my bromeliads. The affected spots gradually became “mushy” and sometimes could be removed by scraping out, each leaving a hole in the outer leaf. Removing the leaf entirely only made the next leaf more susceptible to the problem. If not removed; the mark spread across the leaf causing it to break off, revealing another spot on the leaf inside.

Draining plants and flushing with fresh water seemed to delay the emergence of the marks but nothing stopped them appearing. To add to the confusion not all plants were affected. Tillandsias which were growing to one side and not directly under the frame were quite healthy.

Nidulariums didn’t seem to show as much damage as neoregelias. Other pot plants were unaffected and a tub of parsley needed a lawn mower over it every week to keep it under control.

The vase-shaped bromeliads seemed to suffer most and the tough-leafed genera most of all, particularly neoregelias and billbergias. Tillandsia usneoides hanging on pots was not affected but where it was in direct contact with the timber it desiccated and died. Eventually I felt I should again contact the timber suppliers to see if they could shed any light on the problem. They assured me that nothing in their timber would be the cause. They explained that many vegetable growers used their product without adverse effects to plants or consumers. Finally I took some of the affected plants to them and they analyzed water samples. Their findings were that the levels of salts in the water were not above the accepted levels and could not help me any further. Meanwhile, plants were still dying. Pups would appear; grow quite normally until they reached a reasonable size, and then begin to develop the same trouble as their parents. Even newly purchased plants would show signs of damage within a few weeks.

We decided to move to the Central Coast so we gathered all our plants and put them in shadehouses on the property. These were built of hardwood and the survivors and bromeliads purchased since then are now doing fine. Admittedly, some of the leaves have grown with holes in them where I was able to remove damaged parts, but after 18 months the problem has not re-occurred.

There may have been several reasons for the damage. The shadehouse was a new structure and any excess salts on the surface of the timber had not washed away. We had extremely wet weather during this time which may have caused abnormal leaching of the salts. However; my advice is – DO NOT USE TREATED PINE NEAR BROMELIADS.’

This article is by permission of the Illawarra Bromeliad Society Inc Australia.

Another article written by John Moreland was published in our Journal in March 2003 and told a similar story. At the time it was footnoted by Gerry Stansfield, who wrote: ‘There are a number of other materials one can use for construction and these will vary depending on just how much you are prepared to spend. They all come with their own advantages and disadvantages and, of course, the cost factor is an issue.

However; do not entirely rule out treated timber construction. It will be the cheapest by far; and the easiest to work with and it will almost last forever; but the downside is the treating.

Because the copper cyanide treatment is DEATH TO ALL BROMELIADS it is imperative that the timber is properly sealed. There are a number of proprietary lines available and your local Hardware/Paint DIY can advise.

Fence stain is no good. After sealing, two good topcoats of enamel paint should be applied; making sure the ends of the timber are also coated to stop the timber from bleeding. Don’t be fooled into thinking that old treated timber will not leach out. This is not true, and it could even be worse, as much stronger brews were used in days gone by! Regard all treated timber; both new and old; as requiring special treatment before putting your precious bromeliads under it.’

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