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Air: The Secret Garden Ingredient


Some of you may already be thinking, well, that’s obvious: through transpiration, plants give off oxygen, and they take in our carbon dioxide waste.

That’s true, and very important, but that wasn’t what I meant. What I’m talking about is the circulation of air in the garden.

For someone like me, who wants to cram as many kinds of plants as possible in a small place – somehow being artistic about it – the idea of air circulation came gradually. But if you see certain plants dying or just being morose all the time, you start to wonder.

Finally I read (probably in Graham Stuart Thomas, purveyor of articulate, observant, and good-humored rose information) – finally I read that roses need air circulation. They need air flowing all around them to thrive. So if you cram them in with plants of a similar height, after a while, they start looking cheesey.

They need more air.

When I thought about it, I realized that our wild roses grow with maximum air circulation. They form huge mounds, but those mounds of roses are dotted throughout a meadow – air circulation in between the bushes, and air circulation through the meadow (you only find California wild roses in clear areas, or areas that have once been cleared).


When I found out that my lilies weren’t doing well because I had too many tall plants mashed in with them, I changed my planting habits – and got more flowers and healthier plants. Lilies like their roots cool, so covering their ground with low plants is a good tactic. And this, too, is how I’ve seen lilies grow in the wild: most often in low ground cover or thick duff (the wilderness equivalent of mulch).

Mediterranean plants, such as herbs, like a lot of circulation, too. That makes sense when you consider they are basically chapparal plants, dotted over a stony landscape, often on slopes, where air circulation is even better.

Knowing how plants grow in the wild gives us useful clues about how they’ll do in our gardens – and incidentally, helps us know our plants better. If you have plants which are mysteriously languishing, you might consider giving them a little air.


{ 5 comments… add one }

  • Steve July 22, 2010, 5:40 am

    Pomona, I can’t wait to dig deeper in here – what a treat. I’ve languished a bit on the commenting and visiting. This subject – air – is extremely topical, actually. Many people overlook a very simple concept – space. It seems so many of us want an immediately-lush look, we overlook the overall environment for our little offspring. Next thing you know – we got us a mob. Good post!

  • Cyd July 25, 2010, 10:55 am

    This is so true. You have really put your finger on it with this post Pomona.

  • lostlandscape (James) July 25, 2010, 6:13 pm

    As Steve points out, space and air occupy different sides of the same coin. In my joy for plants I tend to over-plant and deprive plants of the ideal air circulation. Even my bog plants–creatures of total wetness–grow much healthier and fungus-free when they’re not crammed together, pot-to-pot like I grow many of them.

  • Pomona Belvedere July 26, 2010, 8:54 am

    Hm, apparently I have some fellow plant-crammer addicts. Steve, I always learn from your big-picture expertise. Cyd, I’m glad to know that I provided some valuable thinking-out-loud! And James, I suspect we need bigger gardens – or is there a garden big enough?

  • catmint August 1, 2010, 4:26 am

    interesting and thoughtful point. I love plants that grow into each other – I guess they don’t need that much air.

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