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Tuesday, April 28, 2015

Sustainable Living: Managing Annual Wildflowers

Arroyo lupine (Lupinus succulentis) - Mother Nature's Backyard

Annual wildflowers are among the most popular California native plants.  An important part of our natural heritage, they add unique colors and interest to the spring/summer garden.  We covered the basics of annual wildflower gardening in a previous posting:  http://mother-natures-backyard.blogspot.com/2013/01/growing-california-wildflowers.html   Here we consider the sustainability side of growing annual wildflowers.

You may be puzzled about the idea of ‘managing’ wildflowers.  They are, after all, ‘wildflowers’; can’t they can simply manage themselves?  And indeed they can – in the wild.  But local gardens differ in important ways from wild lands.  In the case of annual wildflowers, several gardening choices play a key role in wildflower sustainability.

Removing spent annual wildflowers after seeds are gone

Late spring visitors are often surprised to see golden wildflower stalks among the blooming shrubs in Mother Nature’s Backyard.  One rarely sees drying flower stalks in public gardens; they are often removed as quickly as possible, to preserve the beauty of the garden.  The practice of ‘immediate removal’ of spent flowers does improve the appearance of a garden – but at a cost.  Understanding both the costs and benefits can help you make the right decisions for your own garden.

Our annual wildflowers are remarkably efficient organisms.  They germinate, flower and set seeds in only a few months, allowing them to succeed in our mediterranean climate.  Local annuals survive the long dry season as seeds; so their continued survival is entirely dependent on the formation of healthy, viable seeds.  Without seeds, the wildflowers will disappear from the garden.

The last stage of seed development is the ‘desiccation’ stage, during which seeds lose up to 95% of their water.  This extreme drying allows the embryo to enter a state of suspended animation; there it remains, unharmed by hot, dry weather, through the summer and fall.   When the winter rains begin, the seed and embryo quickly re-hydrate, allowing the embryo to begin growing and thence to germinate.

Seed pods - Arroyo lupine (Lupinus succulentis)

It’s often impossible to tell whether seeds have matured to the desiccation state before they enter it.  If collected too early, seeds may not yet be ready; even if allowed to dry, they may not be viable.   The safest strategy is to allow seeds to dry naturally on the plants. They can then be collected (important for seeds that are heavily eaten by birds) or allowed to naturalize in the garden.   

And that’s why visitors to our garden see drying flower stalks this time of year. They are very noticeable (see above).  But what’s nearly invisible is the process of seed desiccation - taking place in every pod, capsule and flower head.   A true miracle of life, though sometimes not a tidy one!

Annual wildflower stems used as mulch

In Mother Nature’s Backyard we emphasize life-friendly gardening.  We do several things to support the continued survival of annual wildflowers in the garden.

  1. We allow seeds to desiccate on the plants.
  2. We collect some seeds for storage, sharing or propagation. We collect more of the seeds that can be over-eaten by birds (Elegant clarkia [Clarkia unguiculata], Tidytips [Layia platyglossa] and the Goldfields [Lasthena species] come to mind).  The remaining seeds are allowed to self-sow (naturalize) in bare areas of the garden.
  3. When dead plants are finally removed, they are used as mulch, further spreading the remaining seeds and providing summer mulch.  Because ours is a public garden, we try to make our mulch as inconspicuous as possible.
  4. Some areas of the garden are left covered with only a thin organic or inorganic (gravel) mulch.  The mulch helps protect seeds from over-predation by  birds.   And the thin mulch allows them to successfully germinate.

These time-honored practices have been followed by Native Californians and sustainable gardeners for thousands of years.  They mimic the ways of Mother Nature, providing food for animals and humans, while helping sustain the plant species.   They are life-friendly and sustainable.

So when our tidy-up instincts tempt us to remove plants, we remind ourselves of the benefits of waiting, just a bit, for seeds to complete their cycles. We look forward to next year’s wildflowers with hope and expectation.  We hope you’ll consider doing the same in at least a few areas of your own garden.


We welcome your comments (below).  You can also send your questions to: mothernaturesbackyard10@gmail.com

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