In What Makes a Plant Invasive: the first lesson in what not to plant, we discussed how invasive plants are destroying wildlife habitat and costing taxpayers billions of dollars in eradication and control.
Now we will turn our attention to the second lesson in what not to plant.
One of the first things most people do when thinking about a particular plant is read the part of the tag that says “Hardy in zones __ to __”. For example, hardy in zones 4 to 7.
You need to keep in mind that this zone refers solely to average temperature for each zone. Temperature is only one factor you need to know when planning your garden. You also need to know your average rainfall, hours of sunlight, soil type and ph. Some of this information is also included on the plant tags, but only in great generalities. Making your selection based only on this information can create some major problems for you down the road.
For example, I live in Philadelphia, in southeastern Pennsylvania, which was, until several years ago, a zone 6 (now it is zone 7). When I look at the hardiness map, I see that zone 6 extends from Nova Scotia in a band through eastern New England, northern New Jersey, West Virginia, Tennessee, Missouri, Oklahoma, Texas, New Mexico, Arizona, Colorado, Nevada, Washington, and Oregon.
And that is just the United States. I don’t think my Philadelphia garden has much in common with the high mountain areas of New Mexico or the rain-forest environments of Washington State, but if using the hardiness zone map to make my decisions, I would assume that this doesn’t matter.
However, the garden centers are not just attempting to sell us plants from the U. S. If we follow zone 6 around the world, we see that parts of Greenland, Iceland, Sweden, Norway, Germany, Ukraine, Turkey, Iran, Afghanistan, China, Japan, as well as some mountainous parts of South America are also zone 6.
Is the wildlife of my area familiar with plants from Greenland, Iran, or China? I don’t think so. Remember, our objective is to provide for wildlife, not just determine if a particular plant can survive in my garden. So go ahead and throw away the notion of using the USDA hardiness map to inform your plant choices.
A much better decision model would be to become familiar with the plants that are native to your local area. Many of these plants are in danger of extinction; your choice to give them a home in your garden may help to ensure their survival.
A word of caution is necessary here. NEVER remove an endangered plant from the wild to plant in your garden. Also, be absolutely sure that your nursery does not support this practice. Some plants are threatened simply because people are unscrupulously removing them from the wild in order to fill their pockets with a few dollars. It is a sad fact that the rarer something is, the more some are willing to pay for it.
How do you choose your garden plants?
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© 2009 – 2010, Carole Brown. All rights reserved.
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Amen to all that, Carole! Out west we’re lucky to have the Sunset garden zones – pretty complicated, but they take into account a broad range of climate issues.
Soil type/pH can be a big problem, even with natives. I’ve learned the hard way that many plants that thrive on decomposing granite and quartzite within a couple of miles of our house just can’t take our yard’s limestone-based soil. We’ve been using compost, oak leaf mulch, and other amendments to moderate the alkalinity in some of our planting beds, but there are still some natives we can only grow in containers.
Sheri Williamson´s last blog ..I heard she had a job offer in Monrovia…
@ Sheri I didn’t know you had a blog, so now I’m subscribed. Thanks.
Choosing the right plants can be a little complicated at first, but if we do a little homework in our gardens to get to know what is happening in our space, we can save a little money and a lot of water. I have a whole series of articles about planning that I’m working on about getting to know our sites……in time, they will be appearing here. I’m certainly guilty of making impulse purchases because something looks so pretty at the store, even though I’ve done my “homework”.
How many species of hummers in your gardens right now? I miss my grad school colloquiums twice a semester because I’d always book a few extra days to try and find as many hummers as I could.
At least six species in the yard today: several Broad-billeds, lots of Black-chinneds, male Anna’s, female Calliope, male Broad-tailed, and an unambiguous male Rufous plus lots of unidentifiable little orange and green brawlers. My hummingbird garden went almost completely out of bloom when the “monsoon” stalled, but they’ve got feeders and wild agaves to fall back on.
Sheri Williamson´s last blog ..Where do I begin?
@Sheri, it’s s amazing to have all of those hummingbirds. I know gardening in Arizona can be kind of tricky to say the least, so it’s a credit to you that you have little orange and green brawlers hanging around.
I think at times we’re all victims of taking the simple approach or easy way. It’s a lot easier to read a label and say, “Zone 6. Good, that plant will work in my yard.” Finding natives really does take more work. I suppose the answer is dissemination of information so that conservation gardening knowledge is more widespread. You’re doing a good job of this Carole.
When I buy plants for my garden I buy either natives or their very close relatives (unless I’m buying tomatoes). The trouble is that I’m a lazy gardener so I end up rarely planting anything because the research and the trip to the nursery which sells natives are more work.I need to overcome this lethargy.
I just got word that two of the books you wrote about last week are waiting for me at the library so I’ll make a trip there today and dive into some garden reading.
@Alison
Yes it does take a little more work in the beginning as we learn what is native, but I printed out a list of native plants from my state native plant society which I’ve marked up as to which species uses each plant and I carry it with me when I go plant shopping. That way I can make a wish list or at least check up on what I’m buying.
Happy reading!
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