Ruud Kleinpaste: Perennial troubles

This last summer has seen a number of ZB talkback listeners complaining about scarlet runner beans mis-behaving. Two main types of troubles were reported:

1) suddenly no more bean pods were growing despite the plant getting to its normal height.

2) At the start of harvesting mature beans, the leaves begin to turn yellow – going down and down.

Scarlet Runner Beans originate from Central America and they like well-drained soil (loam) in a sunny spot. 

Plant the seeds under a tall support to allow the plants grow up and up, the root systems will survive the winter for next year’s crop. They are perennials!!

These beans are Nitrogen Fixers. They don’t need much Nitrogen (they make their own), but love Potash and Phosphate. 

They are long-Season growers with red flowers, pollinated by bees and bumblebees.

Harvest the mature pods regularly and watering regularly to prevent them from drying out (not toooo wet, please!)

What could cause the sudden troubles with the formation of bean pods?

• Lack of Pollination (not enough pollinators);
• Hot weather, especially when that happens at night – lack of water would make that worse.
• Bees sometimes “rob” the nectar from flowers by chewing them open.
• Leaving pods on the plant too long may reduce future seed production.

I decided to contact my old friend and DSIR colleague from way back: Dr Keith Hammett, a well-known plant breeder and famous for creating amazing new varieties of sweet peas and… 

Dahlias (also a perennial plant!)

He came up with some great stories and a possible solution to the yellowing and ill-thrift of Scarlet runners: In the UK these climbing beans were grown as annuals: plant new seeds every spring. If you’d leave the tubers in the soil they were more than likely killed by frost. (“as would Dahlias” said Keith)

In New Zealand’s warmer climate zones we can keep the tubers in the soil, so they will be able to successfully over-winter (they behave like Perennials). Interestingly, the perennial scarlet runners produce beans a little earlier than the sown scarlet runners.

The comparison of Beans with Dahlias is quite interesting: We can leave Dahlia tubers in the soil for several growing seasons, but the performance of the older, perennial plants falls away. It is the build-up of previous year’s growth that tends to choke the plants.

Top Dahlia exhibitors would only ever grow plants grown from cuttings; “Youthful tissue and all that… with no old stuff in the way”

Keith has three tripods of Scarlet Runners (third season) on the go in his garden. One of them is showing those debilitating features with yellowing leaves….

He attributes that to stress and an old tuber giving up the ghost

For what it’s worth… maybe a good idea to sow new seeds in spring?

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:07):
You're listening to the Saturday Morning with Jack team podcast
from News Talks at be.

Speaker 2 (00:13):
Rude climb passes our man in the garden. He's with
us this morning, killed us.

Speaker 3 (00:16):
Sir Curia Jack. I am in the garden because there've
been a few problems around the gardening to Oh, yes.

Speaker 2 (00:26):
A few problems. Oh, you wouldn't go down well on
my place. Rude, you know nothing but success stories in
the Tame family garden. Actually, you know what I got
to say. Sorry, we'll get into things in a minute,
to get into your various issues. My capsicums this year,
it's the first time I've first summer I've had a
crack at growing capsicums, and I don't want to talk
it up too much, but I've absolutely crushed it. I

(00:48):
don't know what I did, but for some reason, I
reckon I've got maybe fifteen or twenty capsicans on one plant.
Not bad, ah, it's not.

Speaker 3 (00:56):
Although a bit of squats.

Speaker 2 (00:58):
They're a bit sort of they're a bit sort of
short and fat as opposed to they don't get their
kind of long, you know, sometimes you get them. They're
quite nice and long. But they're beautiful red and sweet.

Speaker 3 (01:06):
The gold Yes, that's right. So you sometimes have green
ones that become red as well.

Speaker 2 (01:11):
Or yeah, yeah, yeah, yeah.

Speaker 3 (01:14):
Exactly, you keep them going. No, this is wonderful to hear, because,
to be quite honest, it is really nice to have
fresh capsicums. Whether you fry them or whether you have them,
you know, smashed up into and sell it, that'll be wonderful.
And the irony is that basically all you need is
a little bit of general fertilizer to do it. You

(01:36):
don't need any major troubles there you go.

Speaker 2 (01:39):
Yeah, well it's rear that I'm reporting on a success
from our garden. So I'm pleased that I can do that.
When you get into your perennial troubles.

Speaker 3 (01:46):
Oh yeah, let's do that. But I reckon money. When
he grows a little bit older, will probably love those.

Speaker 2 (01:54):
There is something about growing something that's a really vibrant
red that's quite exciting.

Speaker 3 (01:59):
You know.

Speaker 2 (01:59):
It's just it's just just looks good, you know.

Speaker 3 (02:02):
Anyway, Yes, it is certainly now perennial troubles. This was
an interesting thing because over the last few weeks Pete
Wolfkemp and I have been talking about scarlet runner beans
that caused quite a bit of problem in New Zealand.
And once, you know, once somebody starts, everybody calls up
talk back, and it's like that a little bit. So
that's how that went. So this is the story. Actually,

(02:24):
I started working on scarlet runner beans and I ended
up talking to a friend of mine, a really good
DSAI made from way back, and we ended up talking
about dahlias, and for some silly reason, the problems at
the scarlet runners may well be related to the same
sort of troubles on dahlias. And this is what I
thought I'd better have a chat about. First of all,

(02:47):
what we heard with the scarlet runners is very simple.
There were suddenly no more bean pots growing at certain
stage of their development, despite their normal light and the
normal height and the normal food and all that sort
of stuff, and they basically started turning yellow. The leaves
were going down and down. Was awful. So that that

(03:08):
was the problem, and we thought, and I thought, you
have to go yellow, and they go from gold. I
haven't heard about a new variety of fungus in New
Zealand that this could be, so you know, I had
no idea. So we started talking about scarlett runners full stop.
They come from Central America they like. Also, this is
for people who actually want to ever look at this.

(03:29):
They like well drained soil, loam in a sunny spot.
I reckon. You can grow them really well where you are, Okay.
You plant the seeds under a really tall support so
they can climb up. They go up and up and up,
and then the root systems when they're finally finished at
the end of the season. The root systems will actually
survive the next winter for the next crop. So they

(03:51):
are literally, technically speaking, perennials. They don't need a lot
of nitrogen because they are actually nitrogen fixers. They've got
these these little creatures on their root zone that can
actually take nigrogen out of the air and turn it
into fertilizers, which I think is quite a clever trick
of plants to do. They're long seasons growers. They're regular waterers,

(04:15):
but not do wet please and that sort of stuff,
and you harvest the mature pods regularly. If you don't
do that, you could get into trouble. So what could
cause this trouble with the beans? Lack of pollination, not
enough pollinators, hot weather, you know, lack of water. Bees
sometimes shew the back of the flowers and developing fruit

(04:38):
to get at the at the nectar. And that's not
good either. So I decided to call Keith Hammett. He's
an old maid of mine and he is also well
known for his sweet peas and his New Zealand Daily thing.
And he came up with a really cool story, namely
that the yellowing and the ill thrift of the skylet
runner could well have something to do what he saw

(04:59):
in the UK where he came from. See, in the UK,
these timing beans are grown as annual not as perennials, right,
so you actually get rid of them after a year.
And the reason is very simple because and it's the
same with dahlias. Actually it's very simple. You in the
warm climate you can keep the tubers in the soil,

(05:22):
you know, but not in England, so you really have
to get rid of them otherwise those roots are starting
to go down the gurglar. And if you compare that
what he knows about dahlias, it's quite interesting because when
you leave dailier tubers in the soil for several growing seasons,
the performance falls away. It goes down the gurglers slowly

(05:44):
and it's literally that is not causing the troubles. So
maybe there is this little connection between the same thing
with dahlias that are overwintering and the scarlet runners that
overwinter as well. If you keep them too long, they
go down the gurglar. So he says he's got You've

(06:05):
got them. So what he says is, look, I've got
three tripods of skylet runners. One of them is doing
exactly what all your callers are saying, and he's attributes
to stress and to all the tubers if you like
giving up the ghost literally saying that's it. I've had enough,
I've done so, yeah, all right, exactly. Our idea is

(06:28):
to get new things at new seats in spring to
save you that vessel.

Speaker 2 (06:32):
Yeah. Hey, thanks RhoD that's great, really very good sir.
You have a wonderful weekend, and we will catch you
again soon. Route climb past our man in the garden.
We're stacking with the veg theme right after the eleven
o'clock news. We're going to look at the difference in
cost and quality between the fruit and vegi boxes you
can get as a subscription service versus the fruit and

(06:53):
vegis you get at the supermarket, not so that I'm
producing quiet enough. Caps comes yet to be offering a
subscription service. They're good though, trust me, they're good. I'm
not put a photo up on my Facebook page actually
so you can have a look be impressed at what
growing at the Tame household One time.

Speaker 1 (07:09):
For more from Saturday Morning with Jack Tame, listen live
to News Talks ed B from nine am Saturday, or
follow the podcast on iHeartRadio.