Red Jade Vine, Mucuna Bennetti, stopped blooming

I've had a mucuna benetti for about 14 years now (we live in Bali) and it's been great. But the parent plant (there are 4 offspring from cuttings also) has totally stopped blooming the past 3+ years. It's a HUGE plant now on an arbor and covering perhaps an area about 1,000 sq ft (300 sq m). We haven't cut it back and it appears very healthy, but refuses to bloom anymore. Any suggestions, e.g. cut it way back, or a little, ... We started adding high phosphorus fertilizer to the root area, but doubt that's the problem as a nearby offshoot is blooming very well.
Any advice appreciated.

 

Hi @David L Van Rooy - welcome! Wow, living in Bali with a plant like that is a problem I wish I had - most of us (though not all!) on this forum are in slightly cooler UK! If it has been growing in the same area for that long, it is highly likely to have exhausted the soil, and adding feed is a good idea. You probably need to keep adding it for it to penetrate to enough of the root mass. The offshoot may have room to send its roots outside of that mass, which could be why it flowers well. Have you tried digging in the centre of the parent plant to see how congested the roots are?

 

Well I doubt many here have had much experience of growing this plant in the UK, so personally I dont have a clue.
Just like to say potassium is the feed for flowers not phosphorus

 

Perhaps @strongylodon has a few words of wisdom?

 

Thanks everyone, much appreciated. The roots of this plant extend at least 40m from the base and seem to be all over the place. My garden is pretty much a jungle with lots of plants battling it out. Attached is a pic of the main plant (center and right side) and, as you can see, it's gotten very woody. On the far left is a child plant (cut from this one) that's much younger (~6 years) and blooming every year 3-4 times. Note that the soil here is very rich and the main problem in gardening here is keeping things cut back -- I haven't done so well in that regard. I suspect at least some-to-heavy cutting back is needed for this mucuna since it's gotten so woody.

Looks like I picked the wrong chemical in NPK. Anyhow I'll start adding fertilizer heavier in K now. BTW, I have a LARGE jade vine (strongylodon macrobotrys) nearby that's huge and even more aggressive, and still blooms like crazy nearby, even after 10 years. But the colors may require different chemicals. I've cut that back a bunch to give more room for the mucuna.

Anyhow I'm very open to suggestions/... on how to handle.
Thanks,
Dave

 

Just an update to thank you, especially CarolineL and pete, and let you know all's working well now -- it's blooming again after adding some good fertilizer to it. I'll now continue using compost around it. Thanks again, Dave