Thursday, July 3, 2008

Hale Damage and the Topic of Senescence

We recently had two hale storms on grand island. My hostas were ripped to shreds and I am in the process of cutting them back but was wondering if that might be harmful to next years growth. Not sure if they would be like daffodils and tulips and need the leaves to stay until they yellow. Your help will be greatly appreciated.

Thanks for writing. Your assumption is right on target. In the world of horticulture there is a word that gets thrown around called “senescing” or “senescence”. When perennial herbaceous plants, like your hosta, begin to naturally yellow and die back in the fall we call that senescing. (Funny enough the verb “to senesce” can be difficult to find in some dictionaries, especially as it relates to horticulture and biology). And even though plants will senesce at different times of the year, the general premise holds true across the boards. Typically by that point the plant has achieved its fundamental biological goal of flowering or producing cones or producing spores in the hopes of reproducing and staying alive as a species. It has then maintained foliage to continue to photosynthesize and store nutrient and carbohydrate reserves for next year. By the time a plant yellows it has built up enough to leaf out and/or flower next spring and can thus go dormant for the rest of the off season. For this reason, most garden plants, from spring bulbs to late flowering herbaceous species, will be happiest and healthiest if allowed to keep their foliage until it naturally yellows and dies back.

As far as your dilemma I completely understand. Two years ago I was working at a public garden and a hale storm destroyed the majority of the large leaf plants in the woodland garden and we didn’t quite know what to do. I suppose what I would recommend is to leave what leaves you can. Even if the plants look a little lop-sided or sad, it will be best if they can utilize what leaf tissue is left to build up energy reserves before the fall. However, if they are really trashed then you have to do what you have to do, even though not ideal. You will sacrifice this years flower and the plants might get a slower or later start next year, but luckily hosta are some tough plants, so I can’t imagine you will actually lose any. Perhaps the plants will push out a new flush of growth this year, but I don’t want to get your hopes up in case that does not happen.

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