Perennial sunflower (Helianthus)

A Scary Monster!

It’s Halloween, so it’s time to post about my garden monster. It looks innocent enough and the daisy-like flowers are very attractive. But it’s huge and spreading, so likely to smother many of the plants around it.

I bought this some years ago as a small plant labelled only as a perennial sunflower, no other details. For the first years after planting, the sunflower didn’t grow much. It was in an unfavourable position, with very poor soil and several shrubs close by. It reached about 3 ft. tall, with narrow stems and leaves and carried pretty yellow flowers in the autumn.

Last year I decided to move a piece to an area that was intended to have a sort of prairie-style planting with coneflowers, grasses, kniphofias and verbena bonariensis. I waited to see if the plant would survive the move and got a shock – it’s growth habit had changed entirely!

The new position has much better soil and suddenly this plant was shooting up. And it was bulky too. The leaves were no longer narrow and dainty – they instead grew to about 7 or 8 inches long and were wide, more like the annual sunflowers. The stems kept growing, with no sign of flower buds for a long time. Eventually flower buds started to appear and the stems finished growing as they reached the impressive height of 8 ft.

Yikes! I’d made a big mistake. This was no longer the dainty-looking sunflower that had been struggling on the other side of the garden. The improved position had allowed my unnamed plant to reach it’s true size. It was now a massive monster that threatened to engulf the other plants.

Because the original plant was so much smaller than it was supposed to be, I hadn’t been able to identify the variety. Now I think that it is Helianthus tuberosus – the Jerusalem artichoke. Or it could possibly be a Maximilian sunflower, which is available as seed in the UK. Whatever it is, I am going to have to dig it all up before it can spread any further.

So that’s my scary tale for Halloween…but I’m happy to say that my other helianthus – ‘Lemon Queen’ (pictured below) is much better-behaved. It is just under 6 ft. tall and seems to stay in a large clump, rather than trying to spread itself everywhere. The bees seem to prefer this one too!

Helianthus ‘Lemon Queen’ is a much smaller and better-behaved perennial sunflower and is welcome here.

16 thoughts on “A Scary Monster!

  1. From your description, I suspect your mystery plant isn’t the Maximilian sunflower. I did a post with multiple photos of that one last year — maybe it will help you either identify or eliminate the Maximilian as a possibility. They do get tall, but your description of the leaf doesn’t sound quite right. Notice that the Maximilian leaves aren’t only narrow; they tend to fold, as well. If it is the Maximilian, the thought of you digging it up makes me quiver — it’s my favorite sunflower!

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    1. Thanks for that – it does look different. The leaves on mine were bigger towards the base and the flowers look different too. I think the Jerusalem artichoke is more likely – or it might be something else entirely. (I’m a bit sad about digging it up – might see if some would grow in a large pot.)

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    1. I was shocked by the change in this one – and I did notice that the original bits of the plant had also started to spread in their poor soil. So I was alarmed by the thought of what the bigger one might manage to do!! Maybe I’ll put it in a big pot… 🙂

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      1. I am going to attempt that with my Phygelius – which is still flowering. It has sent out suckers all over the place so I’m worried I might not be able to dig them all out!

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      2. Good luck Jude! It seems that there are a lot of plants that can be invasive but we’re not warned about it before we plant them! (A friend gave me seeds from her phygelius – if I grow some, they may have to go into containers.)

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  2. The brightish (not British) side if it is a Jerusalem Artichoke is that you can eat the tubers. Maybe go into the tuber for lunch business. 🙂 There are people here who plant them in an area where they won’t bother anyone else.

    Several years ago a friend gave us a single small stem of her Canada Anemone. A pretty little white flower that we thought would be a lovely addition to the driveway garden. It has now spread all over and there seems no way to eradicate it. Like many invasive (although this is native) plants, it takes just the tiniest of root hairs to rejuvenate the population.

    Liked by 1 person

    1. We do eat Jerusalem artichokes – and joke about them – over here, so might try to put the plant into a container. ( It’s been so long since I’ve eaten them that I can’t remember if I like them!) Your Canada Anemone sounds as if it behaves just the same as the Japanese anemones do here – very tricky to deal with!

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