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Breeding new pinks by Sue Russell

Breeding new pinks

Professional nurserymen invest considerable resources in the production of new varieties, but breeding new pinks is a fascinating pastime for the amateur gardener, and one that anybody can join in.
The simplest way to produce a new seedling is simply to gather seed from a pink in the garden that’s been pollinated by an insect, sow it, and see what comes up. This is hit-and-miss: you’ve no control at all over what the seedlings will be like. You might find an interesting new plant that way, but the chances are the results will be disappointing. So if you want to influence the outcome you have to be a bit more selective.
First of all, you have to decide what parents you’re going to use. You need a pollen parent and a seed parent. By using two separate parents (rather than using one, self-pollinated, parent) you can introduce characteristics from two different flowers. For example, you might choose a pollen parent that has a really wonderful perfume, and a seed parent that is a particularly beautiful colour. By crossing the two you might just (if you’re very lucky) produce a seedling that has both the perfume and the colour.

The reproductive organs of a pink
The male reproductive organs are called stamens, and they produce pollen. The pollen needs to be transferred to the stigma (the part of the female reproductive organ that is designed to receive the pollen): this transfer of pollen is carried out in pinks, as in many flowers, by insects such as butterflies.

In pinks, each flower has both male and female reproductive organs, but the male organs usually mature and produce pollen first; as the stamens wither away the stigma begins to appear. The purpose of this is to reduce the chances of a pink flower pollinating itself: the progeny are likely to be less vigorous if the flower has been fertilized by its own pollen.

Protecting your flower from pollinating insects
If you’re trying to cross-pollinate a pink you don’t want it pollinated by insects before you get there, so a little contraception is called for. There are several ways you can stop your seed parent being pollinated by a visiting insect, but, if you’ve got your seed parent in a pot, the easiest way is to place the plant inside an insect-proof cage. This is easily constructed from a cat’s carrying basket – not a wickerwork one or a cardboard one, but the sort that is made of plastic-coated wire mesh. Cover the outside of the cage with a material that will let the light and air through but that will stop insects getting through: some fine-mesh netting or gauze will do. Put the pink that’s going to be your seed parent into the insect-proof cage while you’re waiting for the female organs to elongate and become receptive: they’re ready when they’re curled nicely at the tip, like a butterfly’s antennae.

Producing the seeds
With luck your pollen parent will have some pollen ready at the same time as the seed parent is ready to receive it. (This doesn’t always happen, so it’s worth having an alternative pollen parent just in case your first choice doesn’t come up with the goods at the right time). What you need to do is to transfer some pollen on to the stigma. You can do this by cutting a flower off the pollen parent, holding it close to the seed parent’s flower, and letting the stamens brush against the stigma. Alternatively, you can pick up some pollen onto a clean cotton-bud or soft little brush, and transfer it that way. Then put the seed parent back into its insect-proof cage and wait. If your hand-pollination has worked, the petals on the pollinated flower will droop and wither within a couple of days, and that means that the ovules have been fertilised. Then you can remove the insect-proofing, and it’s just a question of waiting until the seeds are ripe.
You can sow the seeds as soon as they’re ready, or you can store them for a while: as long as they are stored in a cool, dry place seeds of pinks stay viable for a remarkably long time. When they have germinated you can prick out the seedlings, as soon as they’re big enough to handle easily. Pink seedlings that were sown in the spring will flower the same year; those sown in late summer will flower the following year.

Assessing the seedlings
This is the really exciting bit! So many new plants, and you’re the first person in the world to see them! It’s only too easy to get carried away and think they’re all marvelous. But what you’re trying to do is to pick out those that are a bit special in some way, so it pays to be really selective. As they come into flower, set aside those which you think are worth looking at more closely, and throw away those which really, in your heart, you know to be inferior. Those which look promising can be potted up further, and watched to see how they do. When you’re assessing each seedling, as well as thinking about flower quality, perfume and so on, think about the following:
Does it have vigour and health? There’s no point in selecting a weak seedling, even if carries lovely flowers. Does it bear plenty of blooms? A plant that only puts out a couple of stems at a time isn’t garden-worthy. Conversely, does it flower itself to death? A plant that weakens itself by over-flowering so that it lives for only one season isn’t very desirable. Is it hardy? A pink that can’t take the winter cold isn’t worth growing.
Take your time assessing your seedlings. Don’t be in too much of a hurry to make your mind up: watch them over more than one season.

Naming a new plant
It’s one thing to breed plants as a hobby, just for your own pleasure and to share with friends. It’s quite another to give it an official, registered name and to try to market it. Before you take such a step, do make absolutely certain that your new plant is genuinely different from and/or perceptibly better than all the other varieties already named. You should consult someone with expertise in pinks for advice.
If you’re absolutely certain that you’ve got a new plant that is really different and particularly interesting, you might decide to name it and register the name with the International Dianthus Registrar.
A new pink, however excellent, will not make your fortune. But if you’ve got something that’s genuinely different from the many, many pinks already on the market you might just earn a few pounds. There are a number of firms that advertise in the gardening press, inviting amateur breeders to submit their plants for evaluation. Eventually a tiny proportion of the new varieties submitted may end up on the market. But you need to be realistic: experts who assess new varieties have a pretty good idea what will make a successful new introduction, and yours just may not quite have what it takes. But even if your plant doesn’t make it onto the market, you can still be proud of it and enjoy it at home.

This article first appeared as a leaflet and Sue Russell has given kind permission for it to be reproduced on our website.