Groundcover Lecture Notes

• Groundcovers and Lawns Origins
• The hungry hunter gatherer
• Lawns represent prey nearby
• Groundcover may represent food plants
• Flowers represent fertility and water
• Lawns
• Also represent cattle and horse ownership
• A cattle and horse owner looks out and sees the grass cut by the grazing of their animals.
• Pasturage and Golf have propelled the lawn industry
• Golf was first developed in China around AD 400
• Lawn ownership and maintenance could be a form of:
• Exercise in Dominance of territory (master of all you see with a weapon in hand to defend it), and target sport (warrior culture).
• Increase in sight lines for security
• Lawn Pros
• Highly attractive, prestigious
• Cool down the areas they are planted in.
• Unequalled for athletic play
• Huge subconscious satisfaction.
• Lawn Cons
• Huge amount of water
• Require regular maintenance
• Gas powered mowers are highly polluting.
• Most of Southern California is naturally averse to lawns
• Increased humidity
• Types of Lawns
• Summer dormant
• Fescue
• High water use but not as much as other summer dormant
• Clumping
• Susceptible to ‘melting out’
• Aerate or Dethatch every several years.
• Creeping red -California native good for shade
• Bluegrass
• High water use
• Fine texture
• Shallow roots -can dry out inland readily.
• Disease susceptible
• Bentgrass
• Very high maintenance -putting green
• Requires lots of water.
• UC Verde Buffalo Grass
• Winter and Summer dormant
• Slow growing
• Only really does well in the inland valleys.
• Grows too slow on the coast.
• Rye
• Excellent regenerative properties.
• Great for heavy use, athletic fields
• Requires regular watering
• Winter dormant
• Bermuda
• Low growing varieties make good putting greens
• Fine textured
• Go dormant in the winter: turf colorant best used as overseeding can be patchy
• Best with regular dethatching
• Dethatch in June here
• Uses ½ the water that Fescue does.
• St. Augustine
• Luxuriant, old fashioned look
• Less watering than fescue, more than bermuda
• Needs dethatching once every 2-5 years
• Dethatch in June, not Fall. Overseeding with rye not the best idea, instead consider turf colorant when it goes dormant.
• You can prevent dormancy by applying high nitrogen in the late fall before it goes dormant, however you have to water more frequently.
• Zoysia
• Marketed as miracle grass on the back of newspaper Sunday circulars.
• Long dormancy period makes it problematic for this area.
• Paspalum
• Great for salty conditions near the seashore; also for Palm Springs lawns.
• Cool season dormancy almost as long as Zoysia, slow growing.
• Kikuyu
• The ‘Surrender’ lawn
• Does not wear as well as bermuda, but can look just like it.
• Lawn like groundcovers
• Dichondra
• Impossible to keep nowadays as the herbicide that allowed it to exist without hours of weekly weeding is off the market.
• Still a great shade groundcover, as is its native cousin, Dichondra californica.
• Related to yams and morning glories.
• Kurapia (Phyla nodiflora cult. “Kurrapia”
• A sterile, low growing cultivar of  once popular water-saving California native ground cover Lippia nodiflora: Kurrapia can be grown and even mowed as a relatively low growing lawn AND purchased in easy to install rolls like sod.
• Dymondia marguerite
• Tough grey-green low growing groundcover for full sun.
• Initial prep and establishment are important: dig amendment in to 8-12 inches deep.so the plant can develop deep roots.
• After about 1-2 years of establishment you can cut the watering down gradually to once every two weeks.
• Will take some traffic after established -however limit events and parties to once or twice a year -do not play football or ball sports on your Dymondia lawn.    
• Specialty Mixes
• Eco lawn
• Patch Mixes
• Shade mixes
• Native grasses
• Bouteloua
• Festuca californica
• Carex (praegracilis and tumulicola
• Groundcovers
• Perception that bare ground is infertile, sterile.
• Fear of erosion
• The concept of ground cover is relatively recent and may have been fueled by the Dust Bowls of the 1930’s.
• Modern reasons for ground covers
• Aesthetics, ground-cover provides a green area of continuity between larger landscape elements and plants.
• Erosion control
• Can prevent hillsides from sliding down if root structure is sufficient.
• Must balance erosion control and fire prevention.
• Some plants might actually increase breakdown of bedrock.
• Always consult a soils geologist if there is a question of hillside failure
• Security
• Perceptively maintained and/or planted areas of landscape make people feel more secure.
• Sightlines created by low groundcovers increase security.
• Groundcover drawbacks
• Water need is more than just bare ground.
• Increased humidity.
• Vermin and pests
• Rats and Ivy
• Midges and Red Apple
• Discourage ground nesting bees.
• Many require maintenance
• Trimming
• Cutting back
• Fertilization
• Thinning
• Some can cause hillsides to come down.
• Iceplant
• Sedum
• Selected Groundcovers
• Iceplants
• Aptenia (Red and Pink Apple)
• Drosanthemum floribundum
• Delosperma
• Lampranthus
• Sedum etc.
• Sedum species
• Asphodelaceae
• Aloe ‘Red Riding Hood’
• Creeping Aloes
• Asteraceae
• Gazania
• Osteospermum
• Dymondia
• Achillea
• Rosaceae
• ‘Pink Carpet’ Roses
• Other low growing roses
• Lamiaceae
• Rosemary
• Salvia
• Ajuga
• Lippia
• Kurapia (see above)
• Thyme
• Sage
• Rhamnaceae
• Cotoneaster
• Ceanothus
• Berberidaceae
• Nandina
• N. purpurea, N domestica dwarf (shade and sun)
• Berberis repens (shade)
• Ophiopogon japonicus nanus

First Day of September Blooms at the L.A. Arboretum and Botanic Garden

Today was oddly cool and the plants here loved it. One really exciting plant to see right now is Puya berteroniana, the 'Turquoise Puya'. It has a rather unusual teal flower with orange anthers, a color combination rarely seen in nature. 

Puya berteroniana, the 'Turquoise Puya'

Puya berteroniana, the 'Turquoise Puya'

Puya berteroniana, the 'Turquoise Puya' closeup, notice the teal 'tepals' and the orange anthers. 

Also to the north of the Puya in the Water Conservation Garden are beautifully scented Sea Daffodils, Pancratium maritimum. These flowers are unusual in that they bloom in the summer or fall sans leaves, creating almost a ghostly look to them. However scary they may look, they make up for it in a very nice scent. They are native to the greater Mediterranean coastal areas and have become naturalized in parts of Southern California. 

Sea Daffodils, Pancratium maritimum. 

Ceiba (formerly Chorisia) speciosa var. 'September Splendor' is usually the first Floss silk to bloom in the fall. It was one of four seedling varieties of the species that were introduced for their ability to bloom in sequence from September to November. Here's a video I did that shows the differences between the four introductions. 

Ceiba (formerly Chorisia) speciosa var. 'September Splendor' 

Shade Trees of the Arboretum Tour Map

Here is a map of the shade trees we covered on Saturday August 4th. 

Keep an Eye Out for Summer Limb Drop

As the afternoons here get hotter and more humid it is the well irrigated trees that can become a threat. Summer limb drop affects trees like the Floss silk tree, The Italian stone pine, and other susceptible varieties. Here is a news interview I did on the subject several years ago after some children were injured by a falling pine tree :

2010 Gardens of California Lecture, Enjoy!

Beating the Heat Lecture: How to Protect Your Plants in Record Temps

BEATING THE HEAT

·      July 6^th -119 degrees F for over an hour here.
Many Plants Scorched.
In the following days trees, shrubs and woody plants start to defoliate.

The Physiology of Heat Damage

·         PWP -mostly a problem with herbaceous plants.

·         Chloroplast damage -sets off a chain reaction in the plant.

o   Increased production of protective proteins

o   Increased production of abscission hormones.

o   Increased production of damaging peroxides.

·         Leaf drop

·         Fruit drop

·         Flower drop

·         Twig drop

·         Leaf scorch

·         Trunk and branch scorch (citrus and avocados)

·         Limb drop in susceptible trees.

What to Do After

·         Mulch

·         Increase irrigation frequency (but do not overirrigate)

·         Do not fertilize

·         Do not overwater

What if More Heat is on the Way?

·         Anti-transpirants?

o   Work by either plugging up the stomata or causing it to close.

o   Can cause overheating, decrease transpiration.

o   Work best in frost situations

·         Misters

o   Are expensive

o   Can cause fungal infestations

o   Require installation and $

o   Cheap barrel misters may be the best bet.

·         Shade-cloth

o   Can injure plants if just ‘draped’ on.

o   Should be installed as a permanent structure.

o   Need to choose right % for the plant.

o   Do not prevent all heat damage.

·         Kaolin

o   Sprays on

o   Helps control some insects as well

o   Irrigation washes it off.

o   Looks terrible.

·         Modify Irrigation

o   Check Evapotranspiration Index

o   Water according to current ET number.

§  Make sure you do irrigation measurement before you do this.

o   Use coffee cups and turn irrigation on for 10 minutes, measure depth in inches.

·         Plant Choices

o   Plants with blue-green coating (glaucous) do well.

o   Plants from South Africa and Madagascar do well.

o   Plants form the Southwest, South and Central America (not all).

o   Many (not all) Australian plants.

o   Plants from temperate areas do not usually do well.

·         Landscape Choices

o   Remember to put heat and sun resistant plants near walls and walks.

o   Go with climate appropriate plants.

o   Build shade structures.

o   Consider a mist system (for you, not the plants).

Links:

Scorch, Sunburn, and Heat Stress

Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops

When it is too hot for photosynthesis: heat-induced instability of photosynthesis in relation to respiratory burst, cell permeability changes and H2O2 formation

Leaf scorch | The Morton Arboretum

Sunburnt plants 'myth' is debunked - Telegraph

leaf-scorch.pdf

Extension Service | Leaf Scorch

8445.pdf

Bacterial Scorch of Trees

Leaf scorch | The Morton Arboretum

Bacterial Leaf Scorch

Homemade Whitewash for Trees

Whitewashing an Avocado Tree

UC IPM: UC Management Guidelines for Sunburn on Avocado

Surround WP (25 Lb) - GrowOrganic.com

Reserach-Summary_Cochran-Dissertation-MBI.pdf

How to prune heat damaged foliage

Impacts of Kaolin and Pinoline foliar application on growth, yield and water use efficiency of tomato (Solanum lycopersicum L.) grown under water deficit: A comparative study

https://cimis.water.ca.gov/

Madagascar Exhibit, Cactus and Succulent Garden are in Fine Form Right Now

One nice aspect of our collection in the summer is that some of the most heavily blooming plants are located near the entrance, making it not a dire hike to see them. Here are some pictures I took today of sections showing bloom that are fairly close to where you come in.

Crazy blooming plants in the Cactus and Succulent Garden. The red flowers are California native Chuparosa (Justicia californica)

Hummingbird navigating through a 'Sunset' Tecoma. 

A gazebo located at the north edge of the Event Lawn. 

The entrance to the Cactus and Succulent Garden. 

Yellow flowering Uncarina decaryi and tall Alluaudia procera in the Madagascar exhibit.  

More Madagascar Exhibit loveliness. 

Closeup of Uncarina decaryi. 

Flowering Crepe myrtle tree on the walk just north of the entrance. 

Here's a map to most of the above locations: Click here. 

Pests Lecture

Thanks everybody who came to the plant information class on insect and other pests.
Here's a page that goes over the orders that we covered in class and more. 
Also, the mammal pests we covered were:
Rats, Raccoons, Bears, Deer.
We also covered: Peacocks, Sapsuckers, Woodpeckers, Snails and Slugs, and Arachnids like ticks and spiders.
And finally,

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7 Coolest Places at the Arboretum.

OK, when it's 117 it's too hot to go anywhere, however when the temps get back down to reasonable (max 102), here's some places to check out here and stay cool. 

Tower of Jewels Is Glorious Right Now

What better way to keep the Hawaii eruptions in mind than to enjoy the splendor that is one of the Canary Islands most striking flowering plants (and the Canary Islands has many striking flowering plants) -the 'Tower of Jewels' (Echium wildpretii).  E. wildpretii can be found on the clinkery lava plains of mount Teide; a still active volcano that is responsible for forming the island of Tenerife. 

Below is a picture of Echium before it bloomed. Notice the silvery, linear pointed leaves. The silver sheen is created by hairs that reflect the heat coming off of the black, heat radiating lava that is common around the volcano. Here is a picture of the plant growing in its native habitat. 

The plant in bloom looks quite similar (except for the pink blooms) to the Silversword (Argyroziphium sandwicense), an unrelated plant that grows on the Hawaiian island of Maui.  This is a phenomenon known as convergent evolution. It is not known if the Silversword attracts hummingbirds. 

Echium wildpretii does attract hummingbirds (and bees), so scroll down and enjoy the show. These E. wildpretii are located next to the south parking lot gate inside the Arboretum. Here's a map.