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Lowenfels: Non-native landscaping plants are an issue

Jeff Lowenfels
Erik Hill

There is a growing debate in the Lower 48 about the use of non-native plants when landscaping. That is why in last week's column I hinted that we should all be questioning what we plant when it comes to trees and shrubs. I will add perennials as well.

The debate was ignited, in part, by a book called "Bringing Nature Home" by Douglas Tallamy, Professor and Chair of Entomology and Wildlife Ecology at the University of Delaware. The book makes a pretty iron-clad case that modern landscapes and increasing development that uses them is destroying the habitat that supports wildlife that ranges from insects to four legged animals and birds.

Douglas' wonderful book, highly recommended by the way, shows how the creation of a suburban landscape changes the ecology of the area. Replacing native trees and shrubs with exotic ones takes away the berries that the birds in the area used to eat and reduces the "normal" insect fare by staggering amounts both in actual numbers as well as diversity.

The result is a loss of wildlife habit almost as severe as paving it all over. Birds, in particular, suffer. Professor Tallamy explains all of this with ample examples and pictures and then offers some solutions, which don't require mankind to move out.

Now, this problem is a very serious one where there is a tremendous amount of sprawling suburbia. Some came to Alaska to get away from the subdivisions with one tree and three bushes where once were woods, meadows and forest. Obviously, it is less severe in most places in Alaska, there being plenty of biodiversity, the thing modern housing and businesses are so great at destroying. All you have to do is walk to the edge of town and there is a million acres of biodiversity around you.

Still, there are reasons that Alaskans might want to at least listen to the debate. Places like Anchorage and the sprawling Matanuska Valley, for two. Kenai as well, I suppose. Maybe even Homer and some of the smaller communities.

What we plant in our yards impacts wildlife. We know this because much of what we plant attracts moose who love to browse on exotics. But what we take out of our yards, sometimes it was the builder or a previous owner, might be the bush that supports swallowtails. Sure, they love the lilacs when they are in bloom and eat the nectar from them, but I am guessing they don't overwinter in them.

We have somewhere around 40 species of butterflies in the Anchorage area. (A really terrific website for reference is www.turtlepuddle.org/alaskan/ak_butterflies.html.) But it is getting harder to find them unless you are walking in the Chugach or on the edge of a spruce forest. It isn't critical. We have them. It's just their numbers are not as great in town as they used to be when town was smaller. And our "town" is growing.

I know it is hard to imagine an Alaskan yard without lilacs. We drool over those who have maple trees and we like those pines that are shipped into the nurseries and box stores by the thousands. We always want that latest perennial being sold or those new plants featured out at the Botanical Garden Nursery. But I doubt anyone has given much thought to how these new plants might fit into an Alaskan ecosystem, other than if it will be edible to the moose.

We lost a lot of stuff this year and people are waiting for cooler weather to replace and to add to their collections. As we do so, we really should at least stop and think a bit regarding the consequences of our actions. We need to at least have the debate with ourselves (and our spouses).

Everyone wants a nicely landscaped yard (well, almost everyone). And this is Alaska where there really is plenty of native habitat left. All that is fine, but we should at least listen to Professor Tallamy. It might not be a bad idea to replace losses with birch and native spruce. Let's at least start talking about it.

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Garden calendar

HARVEST DAY AT THE ALASKA BOTANICAL GARDEN: ENJOY A FALL HARVEST FESTIVAL AT THE GARDEN WITH FAMILY FUN, EDUCATIONAL DEMOS, GAMES, CONTESTS, FOOD, VENDORS, AND MORE SATURDAY. $7 PER PERSON, OR $5 WITH DONATION OF AT LEAST 3 CANS OF FOOD OR BAGS OF GARDEN PRODUCE. KIDS UNDER 5 ARE FREE. FOR TICKETS, CALL 770-3692 EXT. 0 OR GO TO ALASKABG.ORG.

DANDELIONS: THERE IS A SECOND FLUSH OF FLOWERS AND THEN SEEDS COMING. KEEP THE FLOWERS MOWED DOWN IF YOU CAN. ADIOS (APPLIED LIBERALLY), BURNOUT, HOT WATER AND OTHER ORGANIC METHODS OF CONTROL, INCLUDING WEEDING, ARE ADVISED.

POTATOES: IF YOURS HAVE FLOWERED, YOU CAN SNEAK INTO THE PILE AND PULL OUT WHAT I CALL "NEW POTATOES," BUT DON'T TAKE THEM ALL. LET THEM MATURE THROUGH A COUPLE OF FROSTS.

BROCCOLI, CAULIFLOWER: WHAT ARE YOU WAITING FOR? HARVEST.

LETTUCES: SAME

CARROTS: CAN ALWAYS USE THINNING.

TOMATOES: IF YOU GROW OPEN POLLINATED VARIETIES, KEEP THE SEEDS FROM THE BEST FRUITS FOR USE NEXT YEAR.

WASPS AND YELLOWJACKETS: CAREFUL OUT THERE. IF YOU MUST DESTROY A NEST, DO SO AT NIGHT WHEN ALL THE OCCUPANTS ARE AT HOME. OTHERWISE, THEY WILL FLY AROUND FOR A FEW DAYS DESPERATELY SEARCHING FOR HOME.

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Jeff Lowenfels' best-selling books are available at tinyurl.com/teamingwithmicrobes and tinyurl.com/teamingwithnutrients.


Jeff Lowenfels
Gardening