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How Plants Grow from Cuttings
The ability of a plant to grow from a piece of stem taken from a parent plant is related to its ability to heal damaged tissues.
When a plant stem is wounded, there is water loss and other, unwelcome, organisms can enter through the wound. An ability to heal wounds quickly is essential to survival.
Initially the plant cells exposed by a wound collapse and die, sealing the wound. There is an increase in auxin, a naturally occurring hormone, in the plant's cells in the wounded region. | |
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What is a cutting?
A cutting is a piece of plant stem, root or leaf that is encouraged to form roots (or shoots in the case of a root cutting).
These are called adventitious roots (or shoots). |
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Heeled cuttings have a better chance of rooting
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These cells are then stimulated to form a callus or tissue that heals the wound. This same hormone will stimulate the growth of roots on a stem cutting. Under the right conditions your cutting will send out roots or shoots and become a new plant.
Roots form from the young cells in the cambium layer, the layer of cells surrounding the core of the plant stem that is responsible for thickening the plant stem. The presence in the stem of auxins encourages the roots to grow.
These hormones are available to us as rooting hormones, graded for various types of cuttings. Take care when using these hormones as if you apply too much you can damage the plant's tissue and destroy your chances of growing a new plant.
Types of cuttings
Semi-mature or semi-ripe cuttings are taken in late summer or autumn. These usually consist of a stem with a heel attached These still have a propensity to grow which will see relatively rapid root growth. As stem is more mature and has better food reserves it can survive for longer before roots form and can even be rooted outside.
Softwood cuttings taken in spring take advantage of the willingness to grow present in plants at this season. They can be prone to water loss, and are also more susceptible to damping off and disease.
Hardwood cuttings are taken later in autumn, when plants have less urge to grow or form roots. These cuttings have greater food reserves and are less susceptible to disease. They may take many months to root in a cold frame or cloche however.
Root cuttings are pieces of root, with a growth bud that will grow, paeonies are commonly propagated in this way.
Leaf cuttings are leaves that will root, generally from houseplants.
Sometimes a plant will form roots in water- pelargoniums can be grown in this way. |
Plants Grown from Cuttings are Identical
A new plant grown from a cutting will be identical to the parent plant, that is, it will be a clone. Plants grown from seed will show genetic variation, sometimes only minute differences, from the parent plants. |
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