Sweet pea curiosity

Two different flower colours from the same batch of seed.

One of my favourite sweet peas is a variety called Nimbus, and I grew a couple of batches in the garden this year. It's a widely available variety and (unusually for me, as I mostly use well-off-the-mainstream seed suppliers) I got the seeds from Thompson & Morgan.

Nimbus is a dark purple striped variety ('striped' being the official way of describing this type of colour pattern). Most of the plants in this batch are exactly that. And then there's one which looks like this:

Whereas Nimbus is supposed to look more like this:

So, it's a rogue. It's one of those things which is not supposed to turn up in a batch of commercial seed and which would normally be instantly torn out and bundled off to the compost heap in order to preserve the integrity of the variety.

I quite like it though. So it's not going to be exterminated. I want to find out what it is and what it's doing in a packet of otherwise fairly normal Nimbus seeds. As far as I can see there are four possibilities.

1. It might be a sport, or spontaneous mutation. Sweet peas are very prone to this, so it's a strong possibility.

2. It might be an accidental hybrid, if some stray pollen from another variety 'contaminated' the plants during seed production. This is also possible. Sweet peas normally self-pollinate, but that doesn't mean they can't get crossed accidentally, in some circumstances.

3. It might be an 'off type' or rogue inherent in Nimbus as a variety. In which case, other people have probably come across it as well, and I'd be interested to hear from them.

4. It might be a different variety, which got mixed into a batch of Nimbus seeds by mistake. This is also something that easily happens, and there are one or two other sweet peas which have a similar appearance.

Probably the only way to find out is to save seeds from the rogue plant and sow them next year to see what they do. If it's an accidental hybrid, I will probably get a lot of segregation – which is always a good thing as far as I'm concerned (though it's something which would make many gardeners fling their hands up in horror). Of all the above possibilities, I think no.4 is probably unlikely, because although there ARE magenta/maroon striped sweet peas in existence, this one really does look like Nimbus in every respect other than the flower colour. So I think one of the rogue-of-Nimbus explanations is more likely.

My instinctive feeling is that it's a sport, because it looks to me as though the dark purple colour of Nimbus is made by combining a basic magenta colour with a blue overlay over the top (I say that because some Nimbus flowers show traces of magenta as the flowers fade), so this oddity looks to be the basic Nimbus colour without the blue overlay.

Anyway, I won't know until next year, so here are a few other pictures of my favourite sweet peas in the meantime.

Painted Lady is one of my top favourites, and a little piece of garden history. As a named variety it dates back to at least the mid-18th century, which is quite remarkable, as it pre-dates culinary peas as we know them today. It's also a beautiful, elegant, unassuming variety with a lovely colour and an exquisite scent.

Queen of the Isles is another old variety, one of the first to be bred by the legendary sweet pea breeder Henry Eckford and introduced in 1885. It has red and white flaked flowers.

Matucana is frequently described in seed catalogues as one of the oldest cultivated varieties, but it isn't. In fact it's probably not a heritage variety at all. But it is very lovely, with purple bicolour flowers and a scent second to none.