Breeding new

Mills Farm Plants

Warning: breeding new plants may begin as a hobby, but it can turn into an obsession.

We’ve been breeding Dianthus ( pinks) for twelve years.  We began with an unnamed white seedling as our first seed parent.  We chose it because of its perfume: it was heavily scented, and scent was the quality we were seeking more than any other.

The reason why some modern pinks have little scent lies in their ancestry.  In the early years of the 20th century, a famous grower of pinks called Montagu Allwood crossed the old-fashioned pink with the perpetual-flowering carnation.  He was aiming for a hardy garden pink that would flower for a long season, and he called his new pinks Allwoodii pinks.  They flowered from early summer till late autumn, and we still grow many of his pinks today: Doris is one of his most famous creations.  But although the carnation parent conferred a long flowering period, it also affected the perfume.  Not all perpetual-flowering carnations have scent, and some of these new pinks had little perfume.

For us, a pink without perfume is missing the most important factor, so all the pinks we’ve introduced are scented as well as having a long flowering season.  We think that’s the best of both worlds.

Breeding new plants…

…is a fascinating pastime, and one that anybody can join in. What we describe here is breeding a new pink, because that’s what we do ourselves, but the same principles apply to many garden plants.

The simplest way is simply to gather seed from a pink in the garden that’s been pollinated by a bee, sow it, and see what comes up.  This is a bit hit-and-miss: you’ve no control at all over what the seedlings will be like.  There might be a smashing new plant in there, 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 (to provide the pollen, obviously) 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.

Plants have reproductive organs too!

Not anything like ours, but nevertheless clearly recognisable.  The male reproductive organs are called stamens.  

They produce pollen (that yellow, dusty stuff that rubs off on your nose when you sniff a flower).  The idea is that the pollen should 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.

Now, if you’re trying to cross-pollinate a pink you don’t want the bees dashing in there first, so a little contraception is called for.  There are several ways you can stop your seed parent being pollinated by a visiting insect, but the easiest (if you’ve got your seed parent in a pot) is probably 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 a very fine white cotton material 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.  If your seed parent is growing in a flower-bed, protecting it from the amorous intentions of the insects is a bit more tricky; you’ll just have to rig up some improvised insect protection. (If you’ve discovered a handy way of doing this, why not e-mail us and tell us about it?  Then we can add it to this page and share it with everyone else.  To e-mail us, click here.)

Now you can do the work.  Hopefully 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 pollinated flower will fold up like an umbrella within a couple of days, and that means that the ovules (the plant equivalent of eggs) have been fertilised.  Then you can remove the insect-proofing, and it’s just a question of waiting until the seeds are ripe.

Sowing the seeds…

…doesn’t take long.  You can sow them as soon as they’re ready, or you can store them for a while: as long as you store them in a cool, dry place seeds of pinks stay viable for a remarkably long time.  They germinate quite quickly, too: you should see your first seedlings emerging within a fortnight or less.  Other genera may take longer to germinate.  (For detailed instructions on how to sow seeds, look in any general purpose gardening book).

When they’ve germinated…

…you can start pricking out the seedlings, as soon as they’re big enough to handle easily.  We prick ours straight out into little pots, but if you prefer you can prick them out into trays, and then transfer them into pots when they’re a bit bigger.  Then watch them grow, and wait until they flower.  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 fun 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 marvellous.  But what you’re trying to do is to pick out those which 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, miserable 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 very 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 several seasons.

Naming a new plant

It’s very tempting, when you’ve bred a new plant, to think that it’s a world champion.   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.  It might be a good idea to consult someone with expertise in that particular genus: for example, a nursery that specialises in that genus, or a national collection holder.  (The RHS at Wisley should be able to put you in touch with the appropriate person).

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 appropriate International Registrar. (Again, the RHS at Wisley should be able to put you in touch with the right authority, and give you advice about the rules governing plant names.) 

Will this new seedling make your fortune?
No! Forget your dreams: a new plant, however wonderful, is unlikely to make you rich! But if you’ve got something that’s genuinely different from the many, many plants 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. A few guidelines:

If you plan to offer a new variety to one of these firms, don't give away any plants to other people, not even friends and fellow-enthusiasts.
Never send plants to a firm without first obtaining a written agreement from them, setting out what they are and are not allowed to do with it.  Please believe us: a verbal agreement isn't good enough.
Don't have over-inflated ideas about the possible returns.  The firm that gets your plant onto the market isn't doing it for love - they want their share too!  A pink, for example, may sell in a garden centre for £1.50, but the breeder may only receive 1p per plant sold.

But you need to be realistic. You may think your new plant is the best thing since Eve was expelled from Eden, but 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 still, even if your plant doesn’t make it onto the market, you can still be proud of it and enjoy it at home.

The Wisley trials
The RHS runs trials of many plants, including pinks and carnations, at Wisley. These aren’t commercial trials: they are organised so that amateur and professional breeders alike can submit their plants for assessment. The trials are assessed by committees of experts who will recommend any really outstanding varieties for the Award of Garden Merit (AGM), which is the highest accolade that can be offered to a garden plant. Sue Russell (the author of this website) chairs the group that judges the trials of pinks and border carnations: if you’d like more information, write to us or send us an e-mail: click here for an e-mail form.

Good luck!
Breeding new plants of any kind is fascinating, and once you start you’ll be hooked.