When deadheading, where and how does the new flowerhead grow?

If you have snipped the flowerhead off at the stem, how does a new flowerhead bloom from the stem? Does the stem regrow? If it is pruned to a bud, why on every flower that has been deadheaded, do you not see a stub next to the flowerhead (from where the cut was made)? Does the stub naturally die down?

 

Hiya Simon,

I am not entirely sure what you mean but I will just look at the deadheading issue, because the aim of a plant is to indulge in a little "how's your father" ahem, when you remove the flowerhead before it goes to seed, it knows it needs to make new ones so it carries on producing flowers-or rather it carries on producing flowerheads until it knows it has produced seeds. When you dead head a plant you are prolonging it's flowering period.


And to the best of my knowledge stems don't regrow, new ones are produced from buds.

Pruning is not the same as deadheading, as they are done for different reasons.

 

Simon - new growth normally can only occur in one of two places. The terminal bud - ie the bit at the end of the stem, or at a node. A node is where the leaves appear, and new buds form in the axil (the angle between the leaves and the stem). It is only in these two places that the right chemicals are in existance. New growth could either be a new stem or a flower. So if you cut a stem off a plant, you have also removed the terminal bud. So that stem cannot regrow. In the same way if you cut a flower off, which is the terminal bud, the stem cannot grow another flower. In either case new growth must come from a node lower down.

Terminal buds send chemical signals down the plant. If it is a stem/leaf bud, it sends chemicals down the stem which suppress new buds growing lower down. Thats why you pinch out a plant to make it bushier. By removing the terminal bud you have stopped it sending out the chemicals, so the buds lower down are no longer inhibited and start to grow.

If its a flower that has been pollenated, it will also send chemicals down the stem, but this time these inhibit flower buds from forming lower down. The reason being, as Lollipop pointed out, more flowers are no longer needed as the plant is now able to produce seed. In this case removing the pollinated flower (ie dead heading) stops sending these chemical signals.

Growth at nodes also explains how cuttings work. You generally need two nodes (ie growing points). One above the soil to grow leaves and stems, and one below the soil to grow roots.

 

So the flowerhead will not grow again exactly where it was, but from a bud elsewhere along the stem. So when you have to cut certain roses, for example, to a group of five leaves, a new flower will grow from a node at those leaves?
If I were deadheading this rose, where should I do it and where will the new flower appear? :cnfs:

 

When you deadhead a Rose or any other flowering plant, you should cut off the flower and all of the stem back to the last true set of leaves. Don't be confused that there is a set of small leaf like bracts at the bottom of the flower. These bracts are part of the flower and are not true leaves.

Technically speaking, you only need to remove the ovary to encourage the plant to flower more. The ovary is the female part in the centre of the flower that will swell and produce the seeds. This is the part that sends the chemical signals down to the rest of the plant, which can inhibit flowering. However the rest of the flower and stem will die and look ugly - so it is normal to remove the whole lot.

A leaf node, lower down, is the point that has the right chemicals to create new growth, and buds will appear in the angle between the leaf and the stem. It is a matter of chance whether these will be flower buds or stem/leaf buds, but once a plant has started to flower the chance of a new bud being another flower is quite high.

In your picture, you would cut back to the group of leaves in the middle. The small leaf like parts immediately below the red petals are the bracts.

 

Alternatively, you could just snap off the flowerhead, although it is tidier looking to remove back to a leaf node-as Peter says below the ovary of the flower, the new flowers will form from one of the buds along the stem-as Peter says it is a matter of chance as to which bud will produce a rose.

 

I have just been talking to someone who told me when she deadheads her garden roses, she does not bother snipping to a set of leaves or a bud, she simply cuts off the flower its self, and according to this person the new flowerhead just grows at the top of the stem again. How does this fit in with what we have established above?

 

No Simon - that can't happen. New growth must come from a node, it can't grow on top of the old stem.

However that person is right on the first point. To deadhead you only need to snip off the old flower. Which is why deadheading with a pair of shears is essentially just as efficient as doing each flowerhead seperately. You don't need to cut back to a pair of leaves, you only do this to remove the old stems which will die and look unsightly. Sometimes the dead stems just fall off by themselves, so it may look as though the new growth has started from the top of the old stem. But this is really a matter of not understanding exactly what is happening.

 

Thanks for confirming that. On a different note, I have noticed that, when harvesting basil, I simply snip the leaves off one by one, and these seem to just grow back on, from the same stalks, as opposed to appearing elsewhere; you do not still see the redundant leaf stems. Or perhaps my eyes deceive me.

 

I have never grown Basil, but I suspect that your eyes deceive you. The principle of only growing from a node is pretty basic.

Whilst I am not suggesting that this applies to Basil, there are plants that are described as self cleaning. This simply means that you don't need to dead head them as the old flowers tend to fall off by themselves, either with or without the old stalk.