Wednesday, October 7, 2015

You Must Remember This: Summer Dry Natives

"I had a native plant.  It died."

I can't tell you the number of times I've heard this.  The conversation continues: "How often did you water it?"  Usually the answer is three times a week.  Rarely, once a week.  "But more in summer."
My garden back in August.  Having been hosed once every two or three weeks since April. (Except the lawn in the background, watered incessantly by the homeowners association.)
Dear reader, you must remember this.  Plants native to the coastal and foothill regions of California typically get no rain between May and September.  Zero.  Nada.  Zilch.  NO RAIN FOR FIVE MONTHS.  In pictorial form:
Average Rainfall in Irvine (El Toro, 1981-2010) - from

"But these natives are from Northern California. It rains there."  In the winter.  Even San Francisco usually gets no summer rain. (It gets significant moisture from fog– but roots remain dry.)

This year (2015) in Irvine it rained significantly in May, July, and September.  This was abnormal.  Though with global warming, abnormal may be the new normal.  Still, a heavy rain every other month allows well-drained soils to dry completely between rains.  And most of my garden remained stoically dormant through those rains.
Giant Coreopsis (Leptosyne gigantea)  is a lush shrub daisy for four months of the year.  The rest of the year it drops not only leaves but branches.  Stalks only.  Looks dead.  Doesn't matter how much rain it gets.
We are told to adjust our garden watering seasonally, upping it in summer.  New sprinkler controllers even do so automatically.  This works for lawns and East Coast garden plants.  For plants native to coastal California foothills this is exactly backwards, and usually the kiss of death.  We are tempted to "throw a little extra" (water, fertilizer) to keep the garden happy, or to revive a fading plant.  It may grow fast – until it dies.
What is wrong with this picture? (from IRWD's "Rightscape- The Right Plants" educational presentation)  It's inverted! 
Unfortunately WUCOLS, the landscape professionals' guide to water requirements of plant species in California, uses the defective classification system in the above graph to classify plant watering needs.  Summer dry?  You'd never know such a thing existed from WUCOLS.  This leaves most professional landscapers with a very poor track record growing natives.  Sadly, many of them don't even know why.
The cause of death is simple.  Natives are completely defenseless against soil fungi and molds that grow in warm damp soil.  They evolved over millennia never once facing that challenge.   One warm summer day (maybe right away, or maybe they will make it a couple of years) they start browning.  It looks like they need water; they do.  But they can never get water again, because their roots are dead.  In a week or two, they'll be all-over dead, no matter how you try to resuscitate them.  When you pull them out, you may discover the roots rotted away entirely.  Fussy?  That's not what you'd say if you had a half acre of slope to landscape and no interest in irrigating.
This Artemesia 'David's Choice', may it rest in peace (foreground, silvery spikes), was adjacent to overwatered lawn.
What's the answer?

1.  Know your plants.  Some natives are at home in stream beds and swamps.  They will put up with (and may need) lots of water. Ans they may still go dormant in summer.  Others are notoriously touchy about ANY summer water, including that which seeps over from neighboring beds, and they want good drainage even in winter.  These include Flannelbush, Coffeeberry, Wooly Blue Curls, and some of the many varieties of Buckwheats, Ceanothus and Manzanitas.  These are some of our most spectacular natives.   Ironically, desert plants often do better in coastal gardens than the plants that used to grow wild in those very spots, because desert plants are prepared to deal with occasional summer water (originally in the form of desert monsoons.)
From UCI's Arboretum, this Flannelbush (Fremontodendron) wants no water in summer, thank you.
A few natives will put up with variable water (up to weekly) if they can drain decently, including Seaside Daisy, Toyon, 'Howard McMinn' Manzanita, and 'Firecracker' Bush Snapdragon.
Seaside Daisy (Erigeron glaucus) can be slow to establish, but usually tolerates some garden water.  It can grow among roses (sparingly watered) or in transition zones that get a bit of overspray and/or seep from lawns.
Where can you get information about watering needs?  Stay tuned!  I will shortly be publishing best sources for information about watering needs of specific plants.

2.  Hydrozone.  Put plants with similar water needs together, in the same sprinkler controller zone.  Then in summer, turn native zones off.  Or maybe leave them off all the time, especially if your controller runs weekly and not less often.  If you're feeling lucky, you can try a native in the spot the sprinklers miss, but make sure it gets enough water to get established its first year.  If you can't bear the thought of withholding water, put your natives in well-drained pots and water them weekly.

3.  Don't be greedy.  Adopt a conservation aesthetic that allows natives to go dormant in summer.  A weekly or semi-weekly "dusting off" with "Dave's Beer Watering" is all coastal natives need to stay happy.  Sparse watering (and no soil enrichment please!) may result in a slower growing plant.  But hopefully one that will endure.
Sticky Monkeyflower  'Jelly Bean Orange'.  Yes, Sticky Monkeyflowers bloom longer when you water them into the summer.  Then they die.  (You can treat them as annuals...)  This one is tucked in between the never-water Coffeeberry in back and relatively thirsty Wood Strawberries in front so we'll see.
4.  Share knowledge.  Find other gardeners in your neighborhood who are growing natives successfully.  Do what they do.  And learn from their personal plant postmortems– everybody's got 'em.
Tomaz planted his garden next door five years before I got up the nerve.  His success gave me the courage to take the plunge.
4.  Accept imperfection.  If you are cultivating native plants properly, they may be slow to fill in the bare spots, lose a few leaves in summer (or go bare entirely), and bloom for a shorter season than the roses and annuals that your homeowners association waters and fertilizes wastefully.  And you may lose a few plants regardless.  That's OK– it's fun to have a few holes to fill come November.  Otherwise what excuse would we have to buy more native plants?

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  1. Thank you so much. This is exactly the kind of information I need. I have taken out all the grass in our back yard, and am trying to decide what to plant. I want to plant the ones that want no water separately from those that benefit from a bit, but I don't yet know which is which.

    1. Another thing you can do for the no-water plants is raise them up a bit. see "Indian Burial Mounds,

  2. It is not about how much water you are giving to it, thing is everything have its time, your plant's time was completed. Now replace it and plant new one :)