New Clothes for a New Garden

4/22/12

new gloves and hat

     I have bought a new hat and gloves as a way to celebrate gardening in a new place.  As my husband's work here is done, we are moving back to Virginia, and I am thrilled.  I've been waiting for this move for a long time.  I won't be doing extensive gardening at first, because we are renting for a while, but I will be able to plant some annuals in the yard and do some some container  gardening.  And, strangely enough, we ended up renting about six blocks from where we used to live.  I've been packing for the last two weeks, and I have had my fill of boxes, tape, bubble wrap and packing paper.  The movers are coming the end of this week, so this will be my last post for a few weeks.

     Here are a few things I learned about gardening and living in Arizona.

dried grass clippings as mulch

     Nothing decays here, it only dessicates.  I have put grass clippings on my flower garden, and after a year the clippings are still sitting on top of the soil, all brown and dry and crisp.  Since we get very little rain ( four inches last year), and the garden is watered by drip irrigation at each plant, most of the garden gets very little water on top of it.

vinca and celosia

     Solar radiation is much stronger here in the desert southwest (more than twice the solar radiation received by humid regions) because there is no humidity, little living ground cover, and no clouds.  We have gone for months without seeing a cloud.  So the skies can transmit maximal solar energy to the ground where much of it is absorbed, raising the temperature dramatically.  Because of the heat, not much flowers here June to mid-September.  The only flowers in my garden during that time are vinca and celosia.

chard

     It is tricky growing vegetables here.  The last freeze date is around March 1, and the first 100 F day usually occurs in April.  In the fall, the temperature drops to  85 to 90 F by October, but the first freeze date can be mid-November.

     Although I am not a desert-loving person, the desert has its beauty.

Palo Verde tree

My favorite of all natives here is the Palo Verde tree, so golden and graceful.

     Red Yucca with its skyward red spikes.

     Prickly but nicely rounded Golden Barrel cactus.

     I'll be posting in a few weeks from the more humid and much greener climate of northern Virginia.  Hooray! 

What Do We Mean By "Native"?

2/5/12

Palo Verde tree, native to southern Arizona

     I don't know any gardeners that have only native plants in their yards or gardens, although there are gardeners probably striving to grow only natives.  But defining what we mean by native is challenging.

     Many gardeners accept only indigenous plants as native.  Gray's Anatomy of Botany says that to be indigenous there must be scientific evidence that the species has inhabited an area for a great length of time, that it's an integral part of local, evolutionary relationships with other plants and animals.

Saguaro cactus, native to southern Arizona

     But what is a great length of time?  Thousands of years? Hundreds of years?  For example, there were plants that were present in an area of the globe before a glacial period, different plants that were present during a glacial period and different plants after a glacial period.  Can all be considered native?  When European colonists arrived in the Americas hundreds of years ago and introduced species that live on unassisted today, are these species considered native?  If a plant has  become naturalized as a member of the wild flora, needing no human assistance in self-perpetuating, can that plant then be called native?  What of an indigenous plant that migrates to a new area and becomes naturalized without assistance?  Is native a function of time and place?

Lantana, not native to southern Arizona

      Situations like this occur all over the world.  If native status is a function not only of time but also of place, defining place can be a perplexing.  There can be dramatic differences in habitat within a relatively small area.  In my own state of Arizona, within a twenty mile distance, you can go from desert habitat to tundra.  And the plants in the tundra habitat in Arizona are the same as the plants in the tundra of Alaska.

     And consider what we call invasive plants.  They would not exist unless they were better adapted to current conditions than so-called native species.  As Richard Darke says in the book The New American Landscape, " ...most natives are no more than earlier arrivals that established themselves because, at the time, they had a competitive advantage."

gazania, not native to southern Arizona

     Non-native plants fulfill roles that can't be accomplished by natives.  Many food plants grown in North American gardens do not have their origins here.  Many flowers that gardeners grow are not indigenous to their area, but provide beauty, fragrance, color and pleasure, such as the lantana and gazania pictured above that I grow in my yard.. 

     Most gardeners realize that no garden or landscape remains static, that local and global ecologies change.  In the end, I think most gardeners strive for balance among all their plants.

Pink Dawn, Green Stick

Pink Dawn Chitalpa blossoms

4/25/11

     These are descriptive, common names for two trees that grow in my yard.  Pink Dawn is a variety of Chitalpa tree.  I was not familiar with Chitalpa trees until I moved here a year ago.  It is a cross between a Catalpa tree and a Chilopsis (Desert Willow) tree.  My Pink Dawn Chitalpa  is just starting to blossom and will continue to blossom through the fall.  The flowers, a soft pink with a yellow throat, attract butterflies, bees and birds.  The tree has an open limb structure that gives it a lacy look, and it presents a graceful picture.  It is drought tolerant and cold tolerant to minus 15 degrees F, so it does well here in the desert.

Palo Verde blossoms

Palo Verde translated from Spanish means green stick.  The Palo Verde tree's trunk, limbs and branches are green.  My Palo Verde has been blooming for about two weeks.  It will be full of its lemony yellow flowers for a few more weeks.  These trees are breathtaking when grouped together along roadways or parking lots when they are in full bloom.  When their long, thin limbs move slowly and gently in a breeze, it seems like they are dancing to music.  Hummingbirds love to nest in this tree.  It is a most drought tolerant tree, that once established, needs no water.


Palo Verde tree



Chitalpa tree