"Bonsai n the CAT - II"

MY MOST DREADED GARDEN PEST

Help! Some of my Agaves and Yuccas have rotted at the base and collapsed, only to find a mushy and decayed mess. What is causing this? 

It's an attack by the Agave Snout Weevil (Scyphophorus acupunctatus). The picture above shows the adult and the grubs which were embedded in a Yucca aloifolia plant and the damage they cause.

This is a nasty little creature, ½ to 1” long, black, wingless, with a typical weevil snout that bores holes into the base of more mature agave, yucca and other related plants with a base diameter of 2” or more.. Then, it introduces a bacteria which is necessary to cause rapid tissue decay in the plant to feed its white legless grub larvae at the same time it lays its eggs. Once hatched, the larvae feed on the rotting and bacterial rich inside tissue of the agave plant causing it to eventually collapse. It then pupates from larva to adult in the surrounding soil. If this pest is not discovered early on, there is little one can do to save the plant.

OK, now what you may need to do to prevent this nasty creature from destroying your Agave and Yucca plants is apply a systemic insecticide (liquid or granular form) that is effective on grubs. Bayer Advanced Tree & Shrub Insect Control, with the active ingredient imidacloprid (under the trademarked name Merit) has been used effectively. Recommended treatments should be in spring and once absorbed into the plant, should protect your plant for up to a year. Treating the surrounding is also necessary.  Other systemic insecticides can be used if they are recommended for treating grubs. Always follow the directions on the product labels. As much as I hate to use any chemical product, this unfortunately is the only effective way to combat the Agave Snout Weevil once discovered. Observation and immediate removal of infected plants and soil around them is also effective in combating this pest. Agaves grown in containers with sterile soil are much less susceptible as the weevil is soil borne during it’s development. This weevil is doing much damage to commercial Agave crops in Mexico (Tequila, Sisal), therefore is having an economic impact as well. Ironically, it is this grub that is often placed in the bottom of a bottle of Tequila.

Next time you enjoy a Margarita raise your glass and say "Curses to the Agave Weevil"

THE "DOWN TIME" GARDEN

Is the winter period the "ho hum" time of year for your garden?  Does your garden lack the interest that draws you to it during this time?   Well, let's change that image!


Plan for “all season” color, not just “seasonal”.
So much emphasis and effort is placed on our spring to fall garden. The winter garden gets overlooked and is usually unattractive. All season plants that are permanent, preplanned, and integrated into the overall garden design can change that.  Seasonal plants are temporary, and meant only for specific periodic plantings.  The winter season in Austin generally runs from December 1 thru March 31. We reside primarily in cold hardiness zone 8b (minimum coldest temperature ranging between 15 and 20, but a small area around Austin itself is in zone 9a (20-25 degrees). Although we rarely see temperatures that low, we must be prepared for that possibility. Plants must deal with subfreezing temps, ice, sleet,rapid temperature change and wet and cold combinations.

The Challenge

Central Texas native and adaptive plants are mostly deciduous/perennial Evergreens are a garden treasure in Central Texas, but limited. Winter color plants can be seasonal, or all season – cold hardy. Landscape areas should blend both evergreen with seasonal plants. Winter color can be from foliage or flowers –don’t overlook foliage. Foliage can be variegated white/yellow, green, blue/silver, & purple. Marginally hardy or semi-evergreens need protected micro-environments. Cool weather seasonal plants offer more color variety and bloom. Use colorful, eye catching hardscaping to add interest to winter garden Avoid container plantings except in very protected areas as roots freeze much faster than terrestrial plantings. Now let’s look at some plant choices…..

Good plants for off-season temporary garden color in FALL:

Sumac, Bradford Pear, Red Maple, and Crepe Myrtles -for foliage color.

Mums, Copper Canyon Daisy, Fall Aster, Mexican Mint Marigold, Philippine Violet - for flowering

Good plants for off-season temporary garden color in WINTER:

Cyclamen, Pansies, Snapdragons, Dianthus-for winter flowering

Flowering cabbages, kale, or colorful swiss chard for cool weather colorful foliage

Permanent Evergreens to Use
Colorful variegated cultivars of well known Evergreen plants, e.g.

Eleagnus pungens, cvs Maculata, Gilt Edge, Hosobo Fukurin

Abelia grandiflora cv. White Marvel or other variegated cultivars

Yucca filamentosa cvs Golden Sword, Variegata, Gilt Edge, Color Spot

Daniella tasmanica cv. Variegata

Viburnum tinus, cv. Bewleys Variegated

Myrtus communis cv. Variegata

Trachyspermum jasminoides cv. Variegata

Yucca rotundifolia cv. Margaritaville

Tulbaghia violaceae cv Variegata (Society Garlic)

Ophiopogon (Monkey Grass) –variegated, black, dwarf, etc.

Ligularia species and variegated cultivars

Colorful evergreen shrubs and cultivars (other than green)

Silver colored foliage, e.g.

Leucophyllum fruitecens 'silverado‘ (Texas Sage)

Teucrium fruiticans (Bush Germander)

Saphora secundifolia 'silver peso‘ (TX Mt. Laurel)

Yucca pallida (paleleaf yucca)

Dasyliron wheeleri -Wheeler’s Sotol

Silver leafed fan palms, e.g. Brahea armata, Serenoa repens (silver leaf form)

Purple colored foliage, e.g.

Loropetalum chinensis 'plum delight‘ –Chinese Fringe Flower

Deciduous winter color from berries/bark, e.g.

Ilex decidua (Possomhaw Holly) –persistent red berries

Lagestroemia indica cvs (esp. Natchez) –brown exfoliating bark

Green is a color too!!

Evergreen shrubs to consider:

Acca sellowiana (Pineapple Guava)

Michelia figo (Banana Shrub)

Fatsia japonica (for a tropical look)

Roses (earthkind varieties and minis)

Ilex vomitoria (Yaupon Holly) –weeping, upright, dwarf forms

Thuja occidentalis (Arborvitae) –one of few suitable conifers

Podocarpus microphylla (Japanese Yew) -comes in dwarf forms

Cold hardy small palms and cycads

Rosmarinus officinalis (Rosemary) –fragrance, texture, etc.

Punica granatus cv nana (Dwarf Pomegranite) –semi-evergreen

Nandina domestica (only dwarf non-berry cultivars, e.g. San Gabriel)

Malpighia glabra (Barbados Cherry) –semi evergreen

Opuntia cactus –thornless

Saphora secundifolia –TX Mountain Laurel
Sanolina (comes in both green and silver varieties)

There are no winter flowering hardy evergreen shrubs/plants for our area that I’m aware of.

Hardscaping to add winter garden interest. e.g.

Natural materials, e.g Limestone Rocks and boulders, Cedar driftwood

Nostalgia items, e.g. old wagon wheel, garden tools, etc

Décor items, e.g. signs, art work, water features

Why let winter be your garden’s “down time” when it can be nearly as vibrant and enjoyable as the prime spring to fall gardening “prime time”. We are fortunate to not have severe winter conditions in Austin, but with some limitations, can enjoy year round color and visual interest in our gardens.  See our presentation (with plant pictures) on Winter Gardening at www.centraltexasgardening.info/wintercolor.pdf