Thursday, April 18, 2013

St. Augustine Needs De-thatching in the Early to Mid Summer

Almost time to de-thatch!

St. Augustine grass (Stenotaphrum secundatum) is coming out of its winter dormancy and beginning to revive as the weather warms.  The return of warm weather means it’s time to take a close look below the surface to see if the lawn has reached at unacceptable level of thatch.  Thatch is organic matter like leaves and grass clippings that have accumulated at soil level but have not fully decayed.  This accumulation of thatch prevents moisture, air, and fertilizer from reaching the roots, causing grass to become weak and subject to pests and disease as the growing season progresses.  Part the blades and take a look.  If the thatch is more than 1/2” thick, it’s time to remediate.

De-thatching is done by combing the lawn vigorously with a stiff-tined rake or mechanical de-thatcher.  Remove the thatch and as little of the grass itself as possible.  New shoots will shortly appear.  The best time to de-thatch - June and July when the weather is warm and growth is vigorous.

St. Augustine grass is native to the Gulf of Mexico, the West Indies and West Africa, growing along sandy beach ridges, limestone shorelines, and salty and fresh water marshes.  St Augustine thrives in warm weather, bright sun, and moist soil in regions of mild winter temperature.  These lawns brown in winter and so are often over-seeded for a green winter appearance, although a much more water saving approach to browning would be to use lawn dye (also known as turf colorant) to maintain St. Augustine’s green appearance.
Because it spreads via the rooting of horizontal above-ground stems called ‘stolons’, St Augustine can be invasive -although nowhere near as invasive as similar grasses like Bermuda and Kikuyu.  And although St. Augustine lawns cannot be called water-saving, some of the newer varieties, like ‘Palmetto’, are a bit less thirsty than the traditional kinds.

Turf colorants:
Article on positive environmental impact of turf colorants:

Google store page for lawn colorants:

Tuesday, April 2, 2013

Rare Opportunity! “Sapphire Tower” About to Bloom at the L.A. Arboretum

Puya alpestris in bloom last year. 

Puya alpestris bud as of 3/30/2013; this bud promises a more spectacular bloom than last year. 

Puya alpestris, an unusual South American succulent from the high, barren slopes of the Andes in southern Chile and Argentina, is now in bud at the Arboretum and will come into full and spectacular bloom in the next week or two.  An almost 6-foot teal-flowered spike emerges from the heavily serrated grey-green leafed base which grows to 2-3 foot high and 3-5 foot wide.  At full bloom, the flower spike will be heavily covered with bell-shaped teal flowers containing startling orange anthers.  The prickly leaves are 1-2 inches at the base and about 2 feet long.  

Puya is a form of bromeliad, the same family as the pineapple.  The Puya alpestris is often sold as, but should not be confused with, its larger relative, the Puya berteroniana.  

In your own garden,  you can use this plant as a complement to cacti and other succulents.  It takes full sun and poor soil and is drought tolerant.  You will need elbow-length gloves, however, to weed around it’s base in order to avoid scapes from the serrated leaves.  It can be propagated by dividing rhizomes or offsets and even by seed.  The plant is suitable for xeriscaping.  While in bloom, the plant is attractive to hummingbirds.

The Puya alpestris does not usually flower every year so make sure you see this unusual teal-flowered plant while the opportunity is here.  You’ll find our “Sapphire Tower” in the Cactus and Succulent Garden. Keep checking here for updates.

South African Bulbs Flowering in the Garden

South African Clivias blooming near the Queen Anne Cottage

Enjoy the blooms now and plan for your fall planting.  Five of the most popular of the South African bulbs, which do very well in Southern California’s mild winters and dry summers, are Watsonia, Sparaxis, Freesia, Clivia, and Amaryllis. These are from the families of Iridaceae and Amaryllidaceae.  Leaves are usually long, cylindrical, strap-shaped.  Most like full sun -but some do well in shade. .

Watsonia flowers tall on branched stems with both evergreen and deciduous species, ranging in colors from white to peach to scarlet.  Stems and leaves can be large, 2 ½ to 4 or 6 feet long.
Sparaxis is notable for its splashes of contrasting colors on blooms which themselves come in a wide range of colors.  They are well-suited to borders and rock gardens and bloom over a long period in late spring.
Freesia are typically white or cream in older varieties with newer hybrids in a wider range of colors.  Freesias will dry up after bloom and tend to self-sow if flowers are not removed.  Freesias are often prized for their fragrance.
Clivia is an exception to the sunshine rule.  While Clivia like light they do not like direct sun.  It is a good companion for ferns and other shade-lovers with its brilliant orange and orange-yellow bloom.
Amaryllis, also called Naked Lady or Belladonna Lily, are dormant now but will spring to life come the hot weather of August with fragrant pink blooms.  They are drought resistant and tolerate almost any soil. They can take full sun but the blooms will last a bit longer in partial shade.
Anaryllis bulbs blooming on the northwest side of the Bauer lawn in August of last year. 

South African bulbs have become increasingly popular with Southern California gardeners as we have come to appreciate their adaptability to our climate and usefulness in our gardens.  There is a wide  choice of bulbs from online sources well beyond the popular five mentioned here.  You might check out the for more information on available sources of usual and unusual bulbs.  Many purveyors of bulbs, both online and brick-and-mortar, begin their bulb offerings in July with September being the most popular month for bulb sales, just in time for fall planting.