By Tamara Galbraith

Here's a basic primer on how to divide some of your perennials. Don't neglect this fall duty; it's nature's way of giving you free plants!

Just like pruning, dividing should be done in the season opposite of planting, i.e., spring flowering = fall dividing and vice versa. Try to plan your dividing project for a cloudy, slightly cooler day with a good chance of rain thereafter.

Most perennials should be divided every three to five years. However, some, like columbines, poppies and euphorbias shouldn't ever be divided, even if they start to clump. Don't divide woody plants like lavender, rosemary or the bigger artemesias either.

Before starting your division project, thoroughly water all plants to be divided a day or two before you dig in. Likewise, prepare planting holes for the new divisions so they aren't languishing (and drying out) above ground for too long. You can also pot up divisions to build up size, overwintering pots in a protected environment. Make sure your tools are clean and, more importantly, very sharp.

Use a sharp pointed shovel or spading fork to dig down deep on all four sides of the plant, about 4 to 6 inches away from the plant. Pry underneath and lift the whole clump to be divided. If the plant is very large and heavy, you may need to divide it right in the ground with a sharp shovel before lifting the new sections out.

Shake or hose off loose soil and remove dead leaves and stems. This will help loosen tangled root balls and make it easier to see what you are doing. Depending on the root system, divide your plants as follows:

• Spreading root systems that have just a mess of disorganized roots include such plants as asters, bee balm, lamb’s ear, purple cornflowers and many other common perennials. Some can get out of control unless you divide them frequently. Luckily, they can usually can be pulled apart by hand, or cut apart with shears or knife. Divide the plants into clumps of three to five vigorous shoots each. Toss the center of the clump into the compost pile if it looks like it's run its course and is weaker than the outside edges.

• As the name suggests, clumping root systems originate from a central clump with multiple growing points and usually have thick fleshy roots. This group includes astilbes, hostas, daylilies and many ornamental grasses. A sharp knife is handy with these guys, as it is often necessary to cut through the thick crowns to separate the divisions. You can also pry apart these roots with two digging forks held back to back. Make sure at least one developing eye or bud exists on each division.

• Rhizomes are stems that grow horizontally at or above the soil level. Irises are the most common perennial with this type of root system. Divide irises any time between a month after flowering until early fall. Cut and discard rhizome sections that are one year or older and/or showing signs of disease and insect damage. Iris divisions should retain a few inches of rhizome and one fan of leaves, trimmed back halfway. Replant with the "shoulders" of the rhizome showing above soil level.

• Tuberous roots, like dahlias, should be cut apart with a sharp knife. Every division must have a piece of the original stem and a growth bud attached. After division they can either be replanted or stored for spring planting.

Silly as it sounds, dividing is probably my favorite fall gardening chore. When you dig up one daylily and all of a sudden it becomes four...well, for an avid gardener, that's like a magic show and a birthday gift all rolled into one!

By Tamara Galbraith

Welcome September, a month that ushers in slightly cooler temperatures through most of the country and gives gardeners the opportunity to take care of some business in the landscape. Here are a few chores your garden might need through this month:

• Plant flowering bulbs (Gardeners in Zones 8 and higher should wait until around Thanksgiving, however.)
• Divide peonies, irises and daylilies
• Fertilize roses
• Aerate and fertilize lawn with compost, such as Kellogg Topper, and corn gluten meal product (which also discourages weeds)
• Plant cool weather-loving herbs such as chives and parsley, and pot up summer herbs to bring into the kitchen
• Clean up on and around fruit trees and discard split fruit. Remove raspberry plant canes.
• Spray with and soil drench houseplants with Neem before bringing inside for the winter.
• Start seeds of cool season crops like lettuce, spinach, brocolli, cauliflower and root veggies (carrots, radishes, beets, etc.)
• Dig tender bulbs, such as cannas, caladiums, dahlias, tuberous begonias and gladioli. Allow to air dry, and store in dry peat moss or vermiculite. (Gardeners in Zones 8 and higher can generally just mulch over most of these bulbs.)
• Fluff existing mulch or add a new layer where needed.
• Add a thin layer of compost to just about everything, your houseplants and lawn included!

Shade is inevitable in gardens. It is a blessing and a burden; while few plants flourish in the shade, the ones which do flourish are very pretty.

As a garden matures, trees get larger than was planned, shrubs soar and become treelike themselves, and soon there is very little sun to garden in. Many of these problems can be avoided, if trees are planted so their shadows fall on paved areas or the roof of the house. Trees and shrubs can be pruned to let more light through, and some that were planted too close together should be removed, but full-grown trees and shrubs cannot be replaced quickly, so what you can do with the existing shade should be carefully thought out.

There are varying degrees of shade. Deep shade is the most difficult problem. Only a handful of plants will grow in dark shade, and even they would prefer more light. Deep shade is usually caused by dense trees that keep branches close to the ground. Again, thinning is one way of allowing more light, but sometimes it helps to simply cut off the lower branches so more light slips through. Deep shade is also a logical place for a patio or other paved area, which sidesteps the problem of what to plant.

Light shade is much easier to deal with. "Light" means that some sunlight filters through whatever is directly above, or that if nothing is directly overhead but a plant grows in the shadow of something (as on the north side of a house), there is indirect light coming from the open sky above. Many more plants will grow in this kind of shade, and a few, famous for their flowers, actually require it.

For spring and summer planting, here are some great bedding plants for shade gardens. Like most shade plants, these need light but not direct sun (don't count on them in dark entries, for instance.) All are bread-and-butter nursery items or at least easy to grow from seed. Not all are annuals, but they're treated that way and replanted each year.

Bedding begonia: Newer kinds are unsurpassed for masses of neat white flowers. Near the coast they are almost never out of bloom and can be counted on for color in the the fall and even into the winter. Like impatiens, they are best replanted each spring.

Coleus: Since they are grown for their multicolored leaves, pinch back tips to force more branching and cut off flowers to prolong the life of the plant. Most kinds grow two to three feet tall.

Impatiens: In the last few years, exciting things have been happening to impatiens. Flowers are bigger and colors brighter on plants that are denser and more compact. Impatiens will last through the winter, but are best planted anew each spring. One of the best shade plants. New Guinea impatiens are a little different. Grown for fanciful foliage, they do best with a half-day of sun in the morning, light shade in the afternoon. They'll last several years in pots.

Monkey flower: Sold as Mimulus tigrinus, but actually a cross between a Chilean monkey flower and a streamside California species, this has bright yellow flowers spotted with brown along foot-tall stems. It likes shade and moisture.

Wishbone flower: (Torenia fournieri). A bushy little foot-tall plant with purplish-blue pea-shaped flowers. Occasionally found at nurseries, or grown easily from seed.

By Tamara Galbraith

As its common name suggests, the eugenia psyllid, (Trioza eugeniae) attacks eugenia, aka Australian bush cherry, a common ornamental tree or shrub in California.

Throughout the year, the female psyllid lays her gold-colored eggs into the edges of the eugenia leaves. The emerging nymphs later feed on the plant's new growth, leaving unsightly pimple-like galls within the leaves and sticky honeydew as they chew their way through. As you can well imagine, the host plant becomes distorted and weakened from the damage. Complete defoliation can occur in really bad infestations.

Now, for a bit of history: The psyllid was first discovered in L. A. County in 1988 and quickly spread to other parts of California, both North and South (but not, apparently, to the Central Valley). In the early '90s, facing a quickly escalating eugenia psyllid problem, scientists got to work on finding a solution. As if the nasty honeydew and physical damage being done to the plants wasn't enough, there was no known natural enemy of the little beasts at the time.

Enter Tamarixia, a parasitic wasp with a taste for eugenia psyllid nymphs.

Mass releases of the wasp in Southern California have shown great results. In North California, however, experts recommend well-timed pruning of affected eugenias in the spring, with the trimmings left on the ground for a couple of weeks to allow the Tamarixia to do their thing. By following this method, you are essentially taking food out of the psyllid's mouth.

As for identification, adult eugenia psyllids are mostly dark brown with a white band around the abdomen. A yellow sticky-trap hung by your plants is a good way to capture suspected pests and see what you're dealing with. You can also use Bayer Tree & Shrub Insect Control to capture these insects. Be careful about spraying anything, though, as you could also end up killing the Tamarixia. Remember, the least toxic method is always best.

By S. & C. Tollison

Adam's Needle (yucca smalliana) may be just the perfect plant for gardens with a rustic allure. This hearty drought resistant yucca is practically carefree (our favorite part). Adam's Needle is large enough for prominent placement. The annual midsummer bloom is a sure reminder that there is nothing "yucky" about this yucca.

As with most succulents, Adam's Needle will provide a great year-round accent to hardier landscapes. Your rock garden or desert landscape will be greatly enhanced. Seashore gardens will also reap the benefits of such a dramatic plant.

For those challenged yucca owners, don't fret! You won't get "stuck-a" with a lot of yucca care. With the exception of cutting down old flower stalks and leaves, this succulent needs no pruning. Just use gravel or stone mulch and space 3-4 feet apart because of its 4 foot height and width. It requires moderate moisture so keep your watering habits short and sweet.

The succulent yucca leaves are gray and green, curling to form sharp points. Experienced yucca owners are well acquainted with the beautiful white, bell-shaped flowers that emerge in the midsummer sun.

So when pondering your next visit to Plant Depot, consider "yucca-ing it up" with the yucca, Adam's needle.