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Slide Notes

Pampas grass (Cortaderia selloana), a garden plant that has escaped gardens and invaded California wildlands.

This deck produced by
California Native Plant Society, San Luis Obispo
http://cnpsslo.org/

Information compiled from many sources, including California Invasive Plant Council (Cal-IPC) http://www.cal-ipc.org/ "Don't Plant a Pest" Central Coast Version brochure

© 2014 CNPS-SLO
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Don't Plant A Pest

Published on Nov 19, 2015

Invasive garden plants to avoid on the Central Coast of California along with suggested alternatives.

PRESENTATION OUTLINE

Don't Plant A Pest

Give them an inch and they'll take an acre ...
Pampas grass (Cortaderia selloana), a garden plant that has escaped gardens and invaded California wildlands.

This deck produced by
California Native Plant Society, San Luis Obispo
http://cnpsslo.org/

Information compiled from many sources, including California Invasive Plant Council (Cal-IPC) http://www.cal-ipc.org/ "Don't Plant a Pest" Central Coast Version brochure

© 2014 CNPS-SLO

California's Central Coast

  • Plants from all over the world thrive in our gardens.
  • Sometimes they "jump the fence" into wild areas,
  • disturb pollinator populations (bees),
  • and alter natural processes,
  • threatening California's biodiversity and economy
Photograph of French Broom (Genista monspessulana) in flower. French and Scotch broom look pretty in the garden, but out-compete with our native plants in the wild.

You can make a difference

  • AVOID purchasing invasive plants at nurseries
  • if demand declines, nurseries will stop carrying
  • CHOOSE safe alternatives to plant in your garden
  • as demand increases, so will popularity
  • JOIN your local CNPS and spread the word
This picture demonstrates the invasive English Ivy (Hedera helix) destroying forest understory vegetation.

There are many better choices for the garden than English Ivy or Algerian Ivy (Hedera helix). Consider:

Following is a list of the most threatening invasive plants that are disturbing California Central Coast wildlands.

For a complete list of California's invasive plants, please go to http://www.cal-ipc.org/ip/management/plant_profiles/index.php

don't plant

broom - Scotch, French, Spanish, etc
Four plants that go by the common name Broom have invaded over a million acres of California wildlands. The four plants are Cytisus scoparius, Genista monspessulana, Spartium junceum, and Cytisus striatus, aka Scotch, French, Spanish, and Portuguese broom.

"The flowers produce thousands of seeds that build up in the soil over time, creating dense thickets that can decimate entire plant and animal communities. Besides crowding out native plants and damaging wildlife habitat, French broom is highly flammable and creates an increased fire risk to local canyons and forests."

"French broom is becoming a problem in shady canyons throughout SLO county and is most widespread in the Cambria area where it often grows under the pine forest canopy." -Cal-IPC

plant instead

Winter jasmine (Jasminum nudiflorum)
Winter Jasmine (Jasminum nudiflorum) is a slender, deciduous shrub native to China. It grows to 10 feet tall and wide, with arching green stems and bright yellow flowers that bloom in winter.

In California, Winter Jasmine flowers from November to March. The solitary flowers often appear on bare stems, hence the Latin nudiflorum ( literally "naked flower").

Winter Jasmine is valued by gardeners as one of the few plants that flower during the winter months, and is frequently trained against a wall to provide extra warmth. Winter Jasmine can also be planted as a groundcover and can be pruned back spring immediately after flowering

This is a wonderful choice for the garden and has been a recipient of the Royal Horticultural Society's Award of Garden Merit. Slightly drought-tolerant.

Other good alternatives include California natives Lupinus arboreus (yellow lupin) and Lotus scoparius (deerweed).

Sunset zones 2-21, best in cooler climates.

plant instead

Golden Currant (Ribes aureum)
Golden Currant (Ribes aureum) is a a bird, butterfly and bee magnet. A California native shrub with bright yellow flowers that yield edible berries suitable for jams and jellies.

*Ribes aureum* is a 6-10' deciduous shrub with green leaves that turn red in fall and clove or vanilla-scented yellow flowers that bloom April to May. The edible flowers are borne in clusters and may vary from cream to red. Fruit is small (about 1cm), amber to black in color, and IS loved by birds.

*Ribes aureum var. gracillimum is a smaller version of the species. It forms a small thicket about 6 ft high and 2-3 ft wide. It has upright, arching branches, lots of unscented yellow flowers in spring that are popular with hummingbirds, and small shiny green leaves. The yellow berries that turn black as they ripen and are a favorite of many berry-eating birds. Does well in most zones; moderate to regular water.

Don't Plant

Cotoneaster lacteus, C. pannosus
Cotoneaster lacteus or C. pannosus

Late cotoneaster (Cotoneaster lacteus ) and Silverleaf cotoneaster (Cotoneaster pannosus) are large evergreen shrubs native to China. Clusters of white flowers are followed by masses of small red fruits in fall.

Birds have spread the berries and seeds to our wild spaces. Cotoneaster grows rapidly and develops competitive root systems, displacing native plants and animal habitats.

Plant instead

Toyon (Heteromeles arbutifolia)
Toyon, aka Christmas berry and California holly (Heteromeles arbutifolia) is a California native. This evergreen shrub typically grows from 6–16 feet with delicate white flowers in summer and large clusters of brilliant red berries in fall into winter, attracting birds and butterflies and even some mammals in the wild.

Here's a fun fact:
Hollywood may have been named for the Toyon growing in the hills above LA.

Sunset zones 5-9, 14-21. Moderately drought-tolerant, but looks better with moderate water.
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Strawberry tree (Arbutus unedo; not picutred) is a gorgeous evergreen tree to 16 ft tall or more. Its also available in compact, shrub-like varieties that are easy to grow in your garden but won't invade open spaces. Arbutus unedo produces masses of beautiful white flowers and textured strawberry-like fruits. It prefers well-drained soils, and low to moderate soil moisture. Some find Arbutus to be messy when planted next to walkways or patios.

Arbutus unedo serves as a bee plant for honey production, and the fruits are enjoyed by birds. The fruits are also used to make jams, beverages, and liqueurs around the world. Arbutus has been used historically as an antiseptic, astringent, intoxicant, anti-rheumatic, and a tonic.

Fun fact: The tree makes up part of the Coat of arms of Madrid and was mentioned by Ovid in Metamorphoses.

Other great choices include:
- Myrica californica (California myrtle)
- Viburnum suspensum (sandankwa viburnum)

Sunset zones 8-24; little to regular water

Plant Instead

Pineapple guava (Feijoa sellowiana)
Pineapple guava (Feijoa sellowiana) is an evergreen shrub or small tree (4-23 ft) with scarlet and white flowers. The waxy blue-green fruit has a minty pineapple flavor and is widely cultivated as a garden tree.

Pineapple guava is native to the highlands of southern Brazil, eastern Paraguay, Uruguay, northern Argentina, and Colombia, and does not invade our wild lands in California.

Pineapple guava is frost-tolerant and requires only 50 hours of winter chill to fruit. Winter temperatures below approximately 16 °F kill the flower buds; summer temperatures above 90 °F may prevent fruit set. Feijoas are somewhat tolerant of drought and salt in soils, though fruit production can be adversely affected. Tolerant to partial shade; regular water is required while fruit is maturing.

Sunset zones 4-6, 7-24

don't plant

pampas grass or jubata grass
Cortaderia selloana (pampas grass) and C. jubata (jubata grass or toe-toe)

Both of these South American plants have invaded wildlands along the Central coast. While both have invaded parts of Santa Barbara County, jubata grass is the more severe problem in SLO County.

Still widely available in the nursery trade and via mail order, it is the male plants that become invasive but they are nearly indistinguishable from the female.

plant instead

Deer grass (Muhlenbergia rigens)
Deer grass (Muhlenbergia rigens)

A warm season perennial bunchgrass native to California and parts of Mexico. In the wild, deer grass is found in sandy or well drained soils. This large perennial grass is characterized by dense clusters of narrow 3-foot leaves that range in color from silver-green to purple, and stems that reach up to 5 feet and end in a single flower.

Deer grass is extremely drought tolerant and fits in with a water-conscious California garden, and also partners well with other perennials, flowers, and shrubs.

Other good choices include Lindheimer's muhly grass (Muhlenbergia lindheimer), New Zealand Flax (Phormium tenax), Cape thatching reed (Chondropetalum tectorum) and San Diego sedge (Carex spissa).

Sunset zones 4-24; extremely drought-tolerant but accepts regular garden water.

Don't plant

Iceplant (Carpobrotus edulis)
Iceplant, aka Hottentot fig (Carpobrotus edulis) is a nasty groundcover with a vigorous spreading habit.

Iceplant forms impenetrable mats that compete directly with native vegetation, including several rare and threatened plants along the coast.

An even bigger issue for many people is that this Icepant concentrates salts from the air and water into the leaves. Those salts are then released into the soil when the leaves die. This results in such a high concentration of salt in the soil that it makes it very difficult, if not impossible, for other things to be planted nearby, and even for some time after the ice plant is removed. This Iceplant has NO wildlife value on the Central Cost - nothing here can use it for food or pollen. Many people plant it because they think it's fire-resistant, but only when watered regularly.

plant instead

Hardy iceplant (Delosperma cooperi)
There is an non-invasive iceplant (Delosperma cooperi, common name Hardy iceplant) with smaller leaves and brilliant pink/violet flowers that you could choose instead.

Other good choices that tolerate coastal conditions and aren't invasive:

- Beach strawberry/Wood strawberry (Fragaria chiloensis, F. vesca ssp. californica),
- Germander (Teucrium chamaedrys, or T. x lucidrys),
- Showy dewflower aka rosea iceplant (Drosanthemum floribundum).
- Erigeron glaucus (easide fleabane, beach aster, or seaside daisy), a native and beautiful little plant

Sunset zones 2-24; drought-tolerant."

Don't Plant

Periwinkle (Vinca major)
Periwinkle (Vinca major) is an aggressive grower with trailing stems that root wherever they touch the soil. This ability to resprout from stem fragments enables periwinkle to spread rapidly in shady creeks and drainages, smother the native plant community.

From Cal-IPC: "Vinca has escaped from landscaped areas into wildland habitats throughout the Central Coast, and due to its nursery availability there is the potential for increasing problems associated with this commonly used groundcover."

plant instead

Campanula poscharskyana
Instead of periwinkle, consider:

Pachysandra terminalis (Japanese spurge; Sunset z4-10, 14-21; moderate water)

Trachelospermum asiaticum (Ivory star jasmine or Asian jasmine; Sunset z6-24; regular water)

Ribes viburnifolium (Evergreen currant; most zones; needs no irrigation; Cal native)

Heuchera maxima and hybrids (Giant alumroot or coral bells or Channel Islands coral bells) hardiness and water needs vary; some are Cal natives)

Asarum caudatum (Wild ginger; most zones; occasional water; Cal native)

Helleborus species (to many common names to list; varying needs)

Campanula poscharskyana (Serbian bellflower, pictured) is a semi-evergreen trailing perennial with lavender-blue star-shaped flowers from spring to fall. It grows quickly and easily, but is not considered invasive.

Almost all zones; regular garden water.

Thank you!

Thank you for viewing Don't Plant a Pest

The CNPS-SLO website has more information about what to plant (and not to plant) in your garden

http://cnpsslo.org/resources/growing-natives/

- Dealing with Deer in Your Garden
- Native Plants that Attract Birds
- Native Plants with Fragrance
- Native Plants that Attract Butterflies

In addition to their natural beauty, natives provide water-conserving, drought-tolerant and sustainable garden design choices.

Benefits of Native Plants | Native vegetation evolved to live with the local climate, soil types, and animals. This long process brings us several gardening advantages.

Save Water | Once established, many native plants need minimal irrigation beyond normal rainfall.

Low Maintenance | Low maintenance landscaping methods are a natural fit with native plants that are already adapted to the local environment.

Pesticide Freedom | Native plants have developed their own defenses against many pests and diseases. Since most pesticides kill indiscriminately, beneficial insects become secondary targets in the fight against pests. Reducing or eliminating pesticide use lets natural pest control take over and keeps garden toxins out of our creeks and watersheds.

Wildlife Viewing | Native plants, birds, butterflies, beneficial insects, and interesting critters are “made for each other.” Research shows that native wildlife prefers native plants.

Support Local Ecology | As development replaces natural habitats, planting gardens, parks, and roadsides with California natives can provide a “bridge” to nearby remaining wildlands.

Beautiful natural landscapes in California, including the scenic National Parks here, display authentic California flora. Your garden can too.