Monday, November 22, 2010

Under the Asian Collections" Leaf Management Policy" we don't touch these leaves until they turn brown.

Starting this year, in the Asian Collections at he US National Arboretum, we aren't doing "leaf removal", we're doing "leaf management". There is some subtlety here; we don't just "wait for 'em all to fall down and then get 'em all out". In Washington DC, evergreen groundcovers do not benefit from being buried under leaves, and leaves packed around the bases of shrubs make attractive winter home for various mammals that potentially eat the cambium of those shrubs. So we move those leaves. If there's an open space close and it's large enough for us to reasonably add the shifted leaves, we'll do that. If not we'll transport them to the large leaf pile at the Brickyard. At some point they'll be ground to leaf meal and we'll return them to the garden.

There are a lot of tools that we utilize when we engage with the leaves: rakes, baskets, tarps, mulching mowers, blowers, vacuums, shredders....probably some I've forgotten. We would love to forgo the use of blowers and use only rakes, but that's not really possible. We use the least invasive blowers we can and use them as little as possible. But we use them.

Part of our strategy is to look at the leaves as an ongoing process that starts in late November, builds in intensity for a few weeks to mid December and then requires a little regular attendance through the rest of the winter, light tweaking. the sooner we are able to move leaves to their final destinations, the more likely it is that rain will mat them down and minimize their future movement. Conversely, the sooner we remove those leaves that have to be removed the less likely it is that they will be rained on and become more difficult to remove. Like all gardening processes, leaf management is different every year. Different weather conditions determine when leaves fall, whether they blow, when, or even if, they're matted down by rain and or snow. We try to stay flexible.

If this sounds something like what you've been doing all along, hey that's how many of us felt about IPM and "sustainability". I'm thinking any good buzzword is largely new spin on old ideas.

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