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Saturday, December 22, 2012

'Out of the Wilds and Into Your Garden' series

All of the talks from 2009 to the current  'Out of the Wilds and Into Your Garden' season are now available on this blog.  Click on the 'Out of the Wilds' page on the left side of the screen.

Tuesday, December 11, 2012

Why Prune?

Some reasons are obvious.  Diseased or damaged branches need to be removed as soon as possible to prevent the spread of disease.  Growth that presents a safety hazard must also be removed promptly.    But we prune plants for reasons other than safety and health.

One reason is to shape them.   If growing a hedge, we prune out  irregular branches in the beginning and then maintain the shape by regular hedge-trimming.   Similarly, we remove branches that grow in the wrong direction when training a new tree to a pleasant shape.   Some local gardeners take plant shaping to a high level, creating elaborately shaped shrubs in traditional Japanese or European styles.   These examples demonstrate the degree to which certain plants can be shaped.

Gardeners sometimes prune to control the size of trees and shrubs, often with limited success.  In general, plants continue to grow until they achieve their natural mature size.  They will keep trying to achieve this size – or die in the process. That’s why pruning to limit size is an endless task.  It’s far easier to choose a plant with the right natural size in the first place.  This is particularly important with California native shrubs, some of which become quite large.   But choosing a plant based on its mature size makes sense for any plant. 

Southern California’s native trees, shrubs and even grasses need to be pruned for another reason – to keep them youthful and healthy.   Hikers sometimes comment that wild shrubs appear to be pruned by an expert gardener.  In a way they are, but the ‘gardener’ is not who you might expect.

 In truly wild areas, deer, rabbits, elk  - even wildfires, wind and water - prune plants on a regular basis.   Deer and elk browse the fresh growth of trees and shrubs in spring and summer.  Rabbits eat grasses and smaller vegetation.    The plants respond by producing new growth.  If the plant is not over-grazed, the result is a plant that’s fuller, more youthful and more attractive to the eye.

Fires also play a role in plant regeneration.  In the past, wildfires burned local foothills and mountains every 50 to 150 years depending on the area.  Fires are a consequence of our long dry summers and Santa Ana winds.  This weather pattern also occurs in other mediterranean climates like the Mediterranean region, South Africa, western Chile and western Australia.  

Plants from mediterranean climates have adapted to fires over the course of thousands of years.   Many mediterranean climate trees and shrubs have the capacity to re-grow after fires, allowing them not only to survive but also to rejuvenate themselves.    In fact, these plants are so dependent on fire that they literally need periodic fires to survive.   Without them – or their surrogate in the garden - they die prematurely.

Native Californians understood the need for periodic rejuvenation.  In the past, they regularly pruned, divided and even burned plants to keep them young and productive.  Over time, Native Californians became an integral part of the natural cycles of plant life.  They literally became a force of nature.

Most gardens and smaller nature preserves are no longer home to deer, rabbits and other forces of nature.  Even the wind patterns and water flow are altered in populated areas.   But the native plants still need the yearly and occasional catastrophic processes that keep them youthful and healthy.  And that’s where proper pruning plays a role.

Like the deer and rabbits, we need to prune back some of the fresh growth on native shrubs to encourage dense, well-shaped plants.   Like the wind, we need to prune out weak and damaged growth.   And like fire, we occasionally need to prune mature native grasses and some shrubs more harshly.   We literally ‘become’ the deer, rabbits, wind and fire for the native plants in our care.

Pruning native plants is not difficult, but you do need to know how to prune each plant.  Prune a native plant incorrectly – or at the wrong time of year – and you risk damaging or killing it.   The trick is to imitate the natural processes.  Many of us have little direct experience with these processes in the wild.  That means we need to learn how to prune our native plants. 

One easy way is to attend a pruning workshop. The fall/winter pruning season is almost over, but we will have sessions in summer and again next fall.  See 

For more information on pruning common California native plants see our posting on ‘Pruning Common California Native Plants’ (November, 2012).     A great book which includes information on pruning is California Native Plants for the Garden by Carol Bornstein, David Fross & Bart O’Brien (Cachuma Press, 2005). 

Constance M. Vadheim  (Adj. Professor of Biology – CSU Dominguez Hills)

Wednesday, November 21, 2012

Solar Dyeing with Native Plant Trimmings


The Solar Dye Method  is a simple technique that uses a minimum of equipment and energy - and is fun to do.  You can try it with most  native plants commonly grown in local gardens.   You can even use non-native plants, garden vegetable plants and weeds.   Be sure to check (on-line is best) that the plant is non-toxic before you use it in solar dye projects.   Plants in the Sunflower family are not only good dye plants but they also are also safe to use.


·         Large, clear glass/plastic jar (at least 24 oz ; gallon size is better) with a lid* - you may need a second, smaller (at least 16 oz.)  clear jar with lid for mordanting

·         Old cooking pot (equivalent or larger volume than the large jar; enamel or stainless steel is best – aluminum is fine)**

·         Old spoon or stick (sturdy; wood or stainless steel best)**

·         Sieve/colander

·         Plastic dishwashing tub or plastic bucket (for rinsing dyed yarn)

·         Kitchen scale or measuring spoons

·         Hot pads

·         Heat source (stove or burner); optional – see Instructions

·         Rubber household gloves

·         Small mesh lingerie washing bag or mesh paint straining cloth (optional); helpful for containing plant materials /straining the dye bath)


·         Wool or wool-blend yarn (natural color/white/un-dyed; at least 20% wool content– 50% or more is best) -  one or two 100-gram (3-4 oz) skeins/hanks).  

·         Native plant clippings (see below for suggestions***); enough to fill your jar about 2/3 full; woody stems  should be cut into 2-3 inch long pieces

·         Alum mordant - potassium aluminum sulfate (potassium alum) or ammonium aluminum sulfate (pickling/spice alum) : 10% of the weight of the yarn;  for example, if dyeing a 4 oz skein of yarn, you’ll need 10% of the yarn’s weight (0.4 oz) of alum) -  or use a skimpy Tablespoon of alum per skein.

·         Cream of tartar* (5% of the weight of the yarn; in the example, you’d need 0.2 oz of Cream of Tartar to mordant the skein of yarn);  or one level teaspoon of cream of tartar per skein.

* try Smart & Final                  ** try thrift stores if you don’t have these
*** Anything in the Sunflower family (Encelia; Annual Sunflower; Rabbitbush; Coyote Bush; Mule Fat;   Goldenbush; CA Sagebrush; Goldenrod; Telegraph Plant; Yarrow); Black Sage; Toyon; Ceanothus,   Juniper


Preparing the yarn  (can be done ahead of time) 

Rewind yarn into loose skein/hank.  Tie yarn ends together,  then tie skein loosely in three places (use white cotton string or pieces cut off the yarn).  Moisten the yarn thoroughly in lukewarm water (at least 30 minutes).  Squeeze yarn gently to wet.

Dissolve alum and cream of tartar in 1 1/2 cups of very hot water (from the tap or heated).  Wear gloves when handling mordant.  Stir to completely dissolve, then cool to lukewarm.  Place solution in the either the cooking pot or the smaller jar.   Add wet yarn and additional tap water (as needed) to cover.  Swirl yarn gently in the solution.   Cover the pan with plastic wrap (or put lid on jar).  Place in a hot, sunny spot for 2-3 days.

Remove yarn (wear gloves) & rinse well in tap water. Gently squeeze  to remove rinse water.  Dry yarn for later use or put it directly into the prepared dye bath.  Dry, pre-mordanted yarn is good for up to a year; store in a labeled plastic bag until ready to use.


Preparing the dye bath
If needed, cut branches/twigs into 2-3 inch pieces.  If desired,  place plant material into a mesh lingerie washing bag.  Then either: 1) put the plant material in the jar, add tap water to cover and place  in a sunny place for dye extraction, or ; 2) heat the plant material for a short time prior to putting it in the jar.  Note: if  preparing dye from Toyon (Heteromeles arbutifolia) , Laurel Sumac (Malosma laurina), Elderberry (Sambucus nigra), Sugarbush (Rhus ovata) or Lemonadeberry (Rhus integrifolia) use method 1 or heat the dye bath outdoors.   These plants produce cyanide fumes (smell like bitter almond) which are toxic.  

To pre-heat, put plant materials in the old pot and cover them with tap water.   Bring to a boil on high, then turn down heat and simmer 20 minutes.   Cool to lukewarm and transfer material & liquid to the jar.  Cover with lid.  Place jar in a warm/hot sunny place for 5 to 10 days.  Swirl the water every other day.  Dye bath is ready when there’s no more change in color and/or the plant materials appear tan or pale.

Remove plant materials from the dye bath. Strain out small pieces using a strainer/colander or paint straining cloth.   The dye bath is now ready for dyeing.


Dyeing the yarn

Pour dye bath back into the jar.  Soak pre-mordanted yarn in lukewarm water for at least ½ hour; gently squeeze out water.   Place wet yarn into jar; add more water if needed (so the yarn floats freely).  Place capped jar back in the sun and let the sun’s rays work their magic!  Be sure to swirl the contents of the jar gently every day.

It takes 5-14 days to complete the dye process.  You’ll know that dyeing is complete when the yarn remains the same color for several days. Remove the yarn and gently rinse in cool tap water.  Grasp the yarn and rinse using an up-and-down motion.  This rinses and straightens the yarn.  Rinsing is complete when the rinse water remains clear.  Use the rinse water (and the mordant & dye baths) to water your plants.

Dry yarn in a shaded place; fluff occasionally as it dries.   Re-wind yarn into a ball and use the dyed yarn for knitting, crochet or other craft projects.

 Come to a free Solar Dyeing Workshop at Madrona Marsh Nature Center on December 8th (see 'Classes, Lectures and Workshops' page for details).

To learn more about Solar dyeing see 'Solar Dyeing with Native Plant Trimmings' (November, 2012) at :

Questions?   Ask us at:

Thursday, November 15, 2012

Pruning Common Native Plants

Pruning Common Native Plants Used in South Bay Gardens


Plant Species
Trees and Large Shrubs
(Arctostaphylos species
Summer (after blooming/fruiting): Prune as little as possible; removing branched for health only is best
Coyote Bush
(Baccharis pilularis)
Winter: prune to shape if needed.  Start in  first year with low-growing forms.  Thin entire branches (for shaping) or remove up to 1/3 of branch length to encourage new growth
Mule Fat (Baccharis salicifolia)
Fall/winter (main pruning): Thin entire branches (for shaping) or remove up to 1/3 of branch length to encourage new growth
California Lilac
(Ceanothus species)
Spring: deadhead to improve appearance if desired
Summer: Best time for selectively prune branches back to trunk for shaping (after blooming ceases).  Can also prune to shape in late fall.
(Heteromeles arbutifolia)
Spring (dry periods in Feb-Mar.):  Selectively prune to open foliage
Summer (after blooming): Selectively prune to open foliage; remove suckers; hedge prune as needed
Rhamnus species (Coffeeberry; Redberries)
Summer: selectively prune out entire branches to shape    (if desired)
Rhus species (Lemonadeberry; Sugar Bush; Laurel Sumac)
Spring: hedge-shear (if hedging) during active growth after flowering/fruiting
Summer: see spring
Fall: prune to shape as needed.
Matilija Poppy
(Romneya coulteri)
Winter: Prune back entire plant to 4-6 in. tall just prior to re-growth season
Smaller Shrubs & Vines
California Sagebrush
(Artemisia californica)
Fall: Remove top ½ of branch length; do not cut into old wood.  For  ‘Canyon Gray’ remove central upright branches as they appear.
California Encelia
(Encelia californica)
Also Goldenbushes (Hazardia, Isocoma), Gum Plants (Grindelia)
Summer: remove old seed heads if unsightly after birds have eaten seeds
Fall: cut back to about 6-8” in late fall (after flowering for the Goldenbushes)
Bush Monkeyflowers (Diplacus species)
Spring: Deadhead to improve appearance, plant vigor
Fall: Cut back to 4-6 in. above old wood (leave 4-6 buds)
Native shrubby Backwheats (Eriogonum species)
Fall/winter: Remove spent flower stalks; if plants are  woody/ragged cutting back to 2-4 inches may rejuvenate – but may kill plant.  For Giant Buckwheat/St. Catherine’s Lace just trim off spent flower stalks.
Island Snapdragon
(Gambelia/Galvezia speciosa)
Spring: tip-prune (pinch growing tips) for fullness
Spring/Summer: Deadhead as flowers fade; promotes prolonged bloom. 
Winter: Can be cut back to 6 inches in late winter to promote lush foliage
Native Honeysuckles (Lonicera species)
Fall: prune to shape in late fall/winter
Currants & Gooseberries (Ribes species)
Fall: Prune out weak/crossing branches when dormant.  If desired, prune to shape by cutting back to a bud pointing the desired direction.
(Salvia species except Salvia apiana)
Summer: may cut back branches to 3-4 sets of leaves after flowering to encourage a second bloom
Fall: cut back branches to 3-4 sets of new leaves if not so pruned in summer
White Sage (S. apiana) - cut back spent flower stems only
Native Grapes (Vitis species)
Fall: prune/train in late fall when leaves have fallen
Lilac Verbena
(Verbena lilacina)
Year-round:  deadhead to improve appearance
Sub-Shrubs (half-woody plants) and Perennials
Milkweeds (Ascepias species
Fall: cut back to 2-3 inches
Heucheras/Coral Bells
Fall/winter:  remove spent leaves; if plants have gotten too big,  dig up parent plant; carefully divide and replant daughter plants.
Mint family groundcovers
(Hummingbird Sage; Woodmint (Stachys); Wild Mints)
Spring: tip-prune if desired for fullness
Fall: cut back to 4 inches in late fall
Dudleya species
Spring/Summer: Deadhead to improve appearance, or later to provide seed for birds
Fall: cut back dead flower stalks (if not done before)
California Fuschia
(Epilobium species)
Spring: tip-prune if desired for fullness
Fall/Winter: cut back to 4 inches after blooming ceases
Summer: Deadhead as flowers fade; promotes prolonged bloom. 
Fall: Remove spent flower stalks to ground after seeds are gone
Sunflower family groundcovers (Coast Aster, Yarrow, Mugwort)
Fall: Mow or cut back to 2-4 inches
Grasses/ Grass-like Plants; Native bulbs/corms
Cool-season bunch grasses (Festuca; Nasella; Calamagrostis;  Leymus; Melica)
Summer/fall: rake out old dead leaves
Fall: rejuvenate every 2-4 years by cutting back to 4-5 inches; if desired, divide clumps, making sure each clump has a good root ball
Warm-season bunch grasses (Deer Grass; Alkali Saccaton; Purple three-awn)
Spring: rake out old dead leaves; rejuvenate every 2-4 years by cutting back to 4-5 inches
Rushes & Sedges
Fall/winter: rake/clip out old dead leaves; rejuvenate every 2-4 years by cutting back to 4-5 inches; if desired, divide clumps, making sure each clump has a good root ball
Bulbs & Corms
Fall: Dig up every 2-3 years; scatter small bulbs/corms or plant in pots

A few general notes on pruning natives:

·         Always use sharp, clean pruners, saws, etc.

·         Prune for safety and plant heath (disease) as needed, any time of year

·         For large shrubs/trees: never prune off more than ¼ to 1/3 of the foliage – more will stress the plant

·         Don’t prune during excessive heat or when a spell of wet weather is predicted

·         Go slowly – the goal is well-pruned plants, not warp-speed pruning

·         When in doubt, don’t prune.  Come back another day & re-evaluate.



For more complete guide to pruning common native plants see: