QA Forum

Question & Answer

We are discussing Gardening, Growing and Green Thumbs!
With Brian Walters, Diana O'Brien and Pauline Cornish

Question:
I am a 56 year old hobbyist gardener in the U.S. Why do so many native Australian plants require "moist" but "well-drained" soils? The two terms don't seem to go together. Should I always amend my clay soil or just seek tolerant plants?

Answer:
Brian - I don't see any conflict between the terms "well drained" and "moist". It just basically means that the plants prefer soils that are not waterlogged but don't dry out completely. Ideal soils are those that have components that retain moisture but allow heavy rainfall to drain away quickly.

The reason that many Australian plants seem to have the requirement for "moist, well drained" soils is that plants that are native to those sorts of soils in nature seem to be some of the more widely cultivated. There are plenty of Australian plants that will tolerate poor drainage but they tend not be be generally cultivated quite so much.

If you want to grow some of the small, spectacular plants such as Boronia, Banksia, Verticordia, then clay soils will probably need to be worked on to improve drainage. However, plants like Callistemon (bottlebrush), Melaleuca, Leptospermum and a surprising number of grevilleas will grow quite happily in clay-based soils.

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