Kitchen Garden Forum

There's a lively discussion on allelopathy - or plant toxins - developing in a thread elsewhere in this forum: "Is this the ultimate organic remedy for perennial weeds?". It reminded me of that old wives' tale, propounded by Bob Flowerdew no less, that sunflowers are toxic to adjacent plants.

Certainly, tall sunflowers cast shade and also leach all the available water from the soil (a bit like leylandii). But I've had no problems in growing climbing beans up tall sunflowers.

The trick (I find) is to sink an empty cola can beside the sunflower when you plant it. When the sunflower is some three foot tall, pull out the can and replace it with a bean transplant. (That way, you don't disturb the sunflower roots.) Just keep both plants well watered and you get edible seeds plus beans - plus beauty!

Of course, both those plants should be grown in good light.

Another tip is to sink two cans beside the young sunflower and adjacent to the bean, one can being perforated at the sides and base. Keep the perforated can in the ground and keep it filled with water. Your watering problems are over.

I have some lovely pix to illustrate this but I can't seem to imbed jpg URLs here by the IMG method. (Though I have their URLs hosted at ImageShack.) Perhaps some technical wizard could enlighten me? Sorry for the digression...

John, can't help with posting pictures but I can confirm that sunflowers and runner beans grow perfectly happily together. We have a long bean frame on the allotment which stays up all the time (it's very windy here and we need a very sturdy permanent frame) and every year we grow runner beans, climbing French beans, tall peas and sweet peas along this frame, all interspersed with sunflowers and every year they co-habit quite successfully!

True, I think many of the old wives' tales about allelopathy are based on certain gardeners - not plants - being toxic to plants

I have a US friend, a market grower, who has been happily raising beans alongside onions for 30 years - though both are supposed to hate the other. Mind you, he chews so much tobacco that his breath alone would topple a bean at 30 yards...

For the last two years I have grown a mixed bed of Sunflowers, Dahlias, Nicotiana and Nasturtiums and all have thrived together.
You can post photos direct without them being hosted using the attach function below where you type replies, just browse for them on your PC. Make sure they are max 640 x whatever or they bugger up the display.

Thanks, Geoff

Here is a picture of the outer ranks of my sunflower forest a few years back, which shows the climbing beans newly planted around the sunflower roots. (In fact, I sowed the beans too early and I should have let the sunflowers grow another foot. But all was well.)

I grew just over 100 giant sunflowers in the forest and had space for a path up the middle and a little grove within for a deckchair.

More delightful illustrations to follow. (This one's big enough )

Am intrigued. Do the Sunflowers effectively support the Beans or do they mutually assist each other? What sort of spacing do you use?

Essentially, the sunflowers support the beans. The trick is to sow the beans only after the sunflowers are very well up. Or else the beans stifle them. The spacings are determined by the sunflowers. I set them around one foot apart. That's very close for sunflowers but wide for beans - which will grow even an inch apart, given enough water and light.

I spaced those sunflowers closely because I wanted to grow a thick sunflower 'forest'. With a path within leading to a little grove wherein I could put a deckchair and a beer cooler

You can see how it worked in the picture below.

Hi John - certainly looks impressive but how easy is it to pick the beans? It looks a real jungle there.

How easy is it pick the beans? Not very. You need a step ladder plus a spouse to pick you up when you fall into the sunflowers. Frankly, it makes more sense to grow beans up a drainpipe in the usual way. But it wouldn't be as much fun

Hi John,
Sunflowers very impressive but do not see any beans!
JB.

Oh thee of little faith. Below is a close up of a bean vine growing happily around a sunflower stem. Truth is, I did not grow beans up all my sunflowers - just enough to prove it could be done.

Hi John,
Touche pussy cat! Mea Culpa!
JB.