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I have a blue giant hosta. It is in fertile soil and gets plenty of water. I had been dividing it every few years but lately it has started to shrink. I don't want to lose it. How can I get it back?

Update: The plant is smaller than it's ever been before. See pic. The hosta used to cover the entire tank, except for the cap. It is now about 30 years old. Does that have anything to do with it?

enter image description here

J. Musser
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    How much has it shrunk? What do you mean by "lately"? The last year? Two years? Five years? If it is just the last year or two, it may be a weather problem. Big Hosta can be hungry. How much do you fertilize? – Eric Nitardy Sep 21 '11 at 02:13
  • @jmusser Could you please post a photo or two of the Hosta? What is its location in your landscape eg How much shade does it get? Do you divide it once every 3 or 4 years? How are the divisions doing eg Healthy or suffering like the one you're talking about in your question? – Mike Perry Sep 21 '11 at 04:11
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    @jmusser This: [Is Your Hosta Hosting Hostile Pathogens?](http://hyg.ipm.illinois.edu/article.php?id=331) just popped into my inbox, have a read, then please report back if it's relevant or not... – Mike Perry Sep 21 '11 at 14:39
  • @jmusser Can you please post a photo or two of the "damaged" Hosta? I'm pretty certain slugs wouldn't cause a 9ft diameter Hosta to suddenly shrink down to 5ft diameter... – Mike Perry Sep 22 '11 at 04:27
  • Unfortunately I don't have an answer to your question, it's just fascinating to me that hostas can even live that long! I have many varieties, different shapes and sizes. I don't know how long they've been here, since we only bought the house a few years ago, but I like the idea that they may be around even longer than I will! – Sue Saddest Farewell TGO GL Jul 28 '16 at 00:31

2 Answers2

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I have some hostas myself, growing in partial shade; I water them whenever there is a long, dry spell and also feed them (they are in a light, sandy soil which is very free-draining and soon loses nutrients). Every so often, I divide the clumps in spring and, apart from some slug damage, they are all thriving, so, unfortunately, the advice below is not based on personal experience; however, judging from what I have read, I think the problem is likely to be caused by one of more of the following:

  • Planting/ re-planting too low in the soil.

  • Lack of essential nutrients in the soil; you say that it is fertile, but does it contain enough humus, and do you fertilize it from time to time?

  • Ineffective/superficial watering: hostas are moisture-loving plants; sometimes even a soaker hose will fail to supply them with enough in-depth water, and overhead watering is far more effective.

  • Insufficient light: although hostas prefer partial shade, clearly they need enough light to thrive; perhaps the area has become over-shaded...

There is some useful advice on hosta cultivation by the Royal Horticultural Society here.

UPDATE

Further to your comment below, the conditions you describe seem ideal for a hosta; and as it is not showing any signs of disease, the problem could be that your soil has become too acid, which often happens when soil is fertilized and manured for many years. It is worth doing a pH test using a pH meter (the ideal pH for hostas is 6.8-7.3) and, if your soil does prove too acid, you could lime it.

Mancuniensis
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  • It is at the normal planting level and has been for many years now. It gets so much water the soil never dries completely. The soil has a high humus content and is full of earthworms. It has morning sun and afternoon shade. – J. Musser Sep 22 '11 at 01:13
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Hostas need cold in the winter to come back strongly the next year. They tend to slowly lose vigor if they do not get enough cold. What zone are you in and have the winters been particularly mild lately?

Zeddikus
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