Archive for December, 2011

So many times this comes up in conversation. Saving seed of something to grow. And how often it is a waste of time! For a start so many plants grown from seed will not resemble their parent. This goes for almost all fruit trees and all roses for starters. Anything you buy with a name like Babyface, Gala, Red Globe, Hickson, Black Beauty etc will be a cultivar and unless you grow it vegetatively from a cutting it won’t be anything like the original. Even if you can grow it from a cutting its still not that easy. Apart from Plant Breeders Rights legislation which means its illegal to propagate, there is about a 99% chance it is grafted onto a rootstock that also gives the scion (what’s on top) special characteristics. Often resistance to a particular disease but it may make it more compact or more vigorous for example. Many conifers are selected cultivars grafted onto a rootstock.

Most ornamentals you buy from the nursery are vegetatively propagated. So camellias, grevilleas, lavenders, you name it, they are all grown from cuttings.

Another advantage of growing from cuttings is that the material is usually adult. That means it will flower or fruit almost immediately. Plants grown from seed often take years to flower or fruit. That mean 5-6 years to find out that lovely pink tree you took the seed from is now white! The exception to this is some plants that have juvenile leaves – like some eucalyptus species. You can get cuttings of juvenile material to strike but the resulting plant will still be juvenile and will take some time to flower.

Of course there are some plants that are relatively true from seed and some that can’t be grown from cuttings so seed is the only way. Most banksias, dryandras (OK these are now renamed banksias but you know what I mean), hakeas and acacias are like that.

Some other plants are usually grown by other means, such as dividing them up or tissue culture. Most ferns you buy are tissue cultured, some are grown from spores. Many house plants are tissue cultured, also orchids. Kangaroo paws are mostly tissue cultured, a few are still grown from seed and division is possible but too slow for commercial use.

There are some differences in structure between seed and cutting grown plants. Most seedlings have taproots that head straight down for the water table, they aren’t present in cutting grown plants, though over time some roots may take over, become dominant and head downwards to a source of water. But in any case, in most plants, seed or cutting grown, 85% of the roots that take up water and nutrients are in the top 30 cm regardless. In proteaceous plants eg banksias, the specialised proteoid roots form when its wet (so usually winter unless you are irrigating) and they can be extremely shallow – that means don’t cultivate or spray herbicide around the plant if you want to be safe.

By the way – we pretty much hit 10 mm/day evaporation on those last two hot days. I hope you took account of that in your irrigation. My citrus are sizing up and I made very sure to give them two drinks on those days.

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