Botanical Blog

A Cottony Cushion Scale Tale

I finally got my courage up and picked and some grapefruit a few weeks ago.
They had become a beautiful shade of coral pink and the sour memory of the first harvest earlier in the summer has faded from memory. Our citrus tree has multiple grafts of lemon, orange, and grapefruit.
This tree was planted when we first moved here more than 12 years ago, when our back yard was not landscaped and we thought 3 feet from the fence would be plenty of space for the tree. Needless to say, 3 feet is not enough space and the grapefruit graft grows right up to the fence.
We try to keep the tree canopy low so the fruit are easier to reach and to help shade the trunk from the sun. The low branches make getting around the back side of the tree a challenge. I maneuvered my way under the branches and as I reached for the first grapefruit, a white cottony mass on a leaf caught my eye.
Sandwiched between the fence and the tree, I was trying to bend and stretch to get a good look at the pest. It was cottony cushion scale (Icerya purchasi). In years past, I have seen it on the lemon part of tree and on the Japanese aralia (Fatsia japonica), but I usually found only one mature adult that I removed by hand.
This branch had the heaviest infestation I have found in our garden, along the veins of several leaves and even a few small branches. My first reaction was to just scrape off all the insects. But I resisted the urge and decided instead to research the pests to see if that was an effective solution. I picked my grapefruit, extricated myself from the tree and went to learn how to control this pest.
The first step in managing any pest problem is to identify the pest. A mature female cottony cushion scale is very distinctive in appearance. It has a hard, ridged, yellow-tan shell that is approximately one-eight inch in length and covers an elongated cottony white egg sac. The egg sac can grow to one-half inch in length and contain up to 800 eggs. Long white hairs protrude near the edges of the shell.
The adult male cottony cushion scale is rarely seen. It is very small, red in color, and has wings. Eggs hatch quickly in warm weather, but may also hatch in winter. Newly hatched scale nymphs are called crawlers because they have legs.
Unlike most scale, this species retains its legs throughout its life cycle. Cottony cushion scale nymphs begin life as red with black legs and molt several times developing a cottony appearance before producing the hard scale shell. Adult females are typically found on twigs, branches, and trunks of trees while the developing cottony crawlers are found along the veins of leaves.
Cottony cushion scale feed by sucking vital fluids from the host plant and can cause the leaves to drop. It can infest many species of woody ornamental plants such as pittosporum, nandina, and citrus. Severe infestations can cause twig and branch dieback, weaken the plant, and reduce fruit production. They excrete honeydew which supports the growth of sooty mold and attracts ants.
The scale pests are normally controlled by their natural enemies, the vedalia beetle (Rodolia cardinalis) and parasitic fly (Cryptochaetum iceryae). The natural enemies can be disrupted by ants, insecticides, and excessive dust in the environment. Keeping the dust down, controlling ants with baits and barriers, and not using insecticides will allow the natural predators to control the scale.
The vedalia beetle was introduced to the United States from Australia in the 1890s and saved California’s citrus industry from destruction from scale infestation. The mature vedalia beetle appears similar to the lady beetle we see in the garden (red with black spots), but smaller in size. The female beetle lays reddish, oval shaped eggs on the outside of the cottony cushion scale egg sac. When the vedalia beetle eggs hatch, the larva burrow into the egg sac and feed on the scale eggs. Adult vedalia beetles also feed on all stages of cottony cushion scale.
The parasitic fly inserts its eggs into the cottony cushion scale, where the scale insect is destroyed by the developing fly larvae. The adult flies emerge from the scale by creating a hole in the shell.
Armed with this knowledge, I returned to the grapefruit tree to look for natural enemies. The infestation initially looked bad and I was not optimistic. But, we do not use pesticides, have little dust, and there are no ants in the tree.
I brought a hand lens and even though it was the middle of the day, the area between the fence and the tree was shady so I brought a flashlight. I sat down under the infested branch, turned on the flashlight, and examined some adults . . . vedalia beetle eggs studded the scale egg sacs! I could not believe my eyes! I did not find any mature adult vedalia beetles, but I found empty pupal skins which is evidence of the larva maturing to adults. Relieved to know that nature was going to take its course, I left the beetles to do their work.
Pesticides are not recommended for the control of cottony cushion scale and I can see why. It has been several weeks since my first observations and the amount of cottony cushion scale is declining. I am sure in a few more weeks the scale will be gone and the vedalia beetles will move on to find more food in the neighborhood.
For more information on managing ants and numerous other pests, visit the University of California Integrated Pest Management Web site: http://www.ipm.ucdavis.edu or contact the Solano County Master Gardeners Office located at 501 Texas St. in Fairfield.
- Sharon Leos

Gardens suffer at foreclosed homes

This spring my dog and I were out walking and we turned down a street that is not usually on our route.
It had been a few months since we had last been by. A few houses down from the corner, was a house with a climbing rose in full bloom.
The dainty, pink rose entwined around a low fence separating this house from its neighbor. The rose had jumped the space between the fence and the house, clambered up a porch column and reached the roof. From there, it had sprawled across the roof and climbed the chimney.
From the street it looked as if one third of the house was resting in an airy, pink pillow. The house resembled a magical cottage straight out of a fairy tale. So if the scene was so enchanting, why was my heart sinking?
I suspected that the rangy rose was a sign of something amiss. Sure enough, I spotted weeds coming up between the mounds of moss and ferns in the front planting bed. I could see through the front windows that the house was empty.
Even then, I could tell the landscaping had been carefully planned. I thought of the hours of design and the care that had gone into this garden. I knew that the soil had been carefully worked, the fertilizer spread, the weeds pulled and the shrubbery lovingly pruned. I imagined the beautiful bouquets of flowers that must have been picked and brought into the house.
As the months passed and it got warmer, more and more houses ended up empty or with “for sale” signs planted in the front yards. Frequently the first outward sign of something wrong was a dying lawn to be followed by dying shrubbery as lack of water took its toll. In some yards weeds grew knee high.
The home foreclosure blight has brought such sadness. People have lost the safety and security of their own four walls surrounding them. They have lost their dream. But for those with a passion for gardening, they’ve lost something even more.
Gardeners have lost that place of greenery and beauty that they helped create, that calm oasis where they could escape from the outside world. When a well-loved garden dies, whether from illness or death of its owner or from languishing in foreclosure, there is an immense sadness. Some wonderful, vibrant growing entity is gone; all that effort undone.
I hope that perhaps the gardener in that first house had shared cuttings or bulbs from her garden with her friends. Or that perhaps she potted up a cutting for herself as she left. I hope her garden lives on in other locations as well as in her memory.
Many cities have passed new laws requiring banks or mortgage companies to maintain the homes and landscapes that are now their responsibility. Hopefully, this can help some of the gardens and landscapes stay alive and beautiful and help to create the character and soul of our neighborhoods.
- Karen Metz

Singing the praises of geraniums

I cringe when I hear the words, “Oh, about the only thing I can grow are geraniums,” as if this remarkable plant were on the lower end of the food chain of the plant world.
Geraniums have so very much to offer. Lots and lots of variety to choose from, long periods of color, very interesting leaves, enticing scents, hardiness, drought tolerance, a multitude of bright, vivid, even bold colors, as well as soft, gentle pastels -- including white, relatively pest free, and, yes, admittedly, they are relatively easy to grow.
Who hasn’t “borrowed” a slip of geranium from a plant growing along the street or a neighbor’s home, stuck it in water, popped it into the ground, and now has a full-blown bushy, flowering plant in their yard? But there is more to know about geraniums that that.
Geranium is a genus of 422 species of flowering annual, biennial, and perennial plants that are commonly known as the cranesbill. It is found throughout the temperate regions of the world and the mountains of the tropics, but mostly in the eastern part of the Mediterranean region.
Confusingly, “geranium” is also the common name of members of the genus Pelargonium, which were formerly classified in the cranesbill genus. In the United States, true Geraniums are frequently distinguished from the less hardy Pelargonium as “hardy geraniums” by gardeners and in the horticultural trade. One can make the distinction between the two by looking at the flowers; geraniums have symmetrical flowers, while the Pelargonium has irregular or maculate (spotted) petals.
Plants can be bought at nurseries or you can easily start your own from slips. Simply remove cuttings 3 to 4 inches in length from the tip of the stem. Shorter cuttings can be taken if necessary. Strip off the lower leaves to facilitate sticking the cuttings in the rooting medium. Perlite or sharp sand alone or mixed equally with sphagnum moss is an ideal medium for rooting cuttings.
Place cuttings 1 inch deep in the medium and water thoroughly. Place container in a north or east window until rooted. Rooting occurs best with soil temperatures of 72 to 75 degrees F. This generally takes three to four weeks.
Water sparingly during this rooting period -- the trick to successful rooting is to keep the cuttings fairly dry. When cuttings have rooted, place them in 4-inch pots. After the cuttings become established (approximately one week), start fertilizing with a liquid fertilizer such as 20-20-20 or 15-30-15 at one-half the recommended rate of application. Make monthly applications thereafter until the plants are planted outside.
The variety of flowers, leaf patterns and color, and scents to choose from are far too numerous to list here. However, the most common types fit into one of the following groups:
Zonal: This group is loved for its big, attractive flower heads that bloom white, pink, orange, red or purple. The leaves have a dark zonal pattern on the leaves.
Fancy leaved: Some zonal geraniums have fancier leaves, edged or banded by colors such as yellow, white, burgundy or coral.
Ivy: This type has ivy-like leaves and a trailing habit, which makes them perfect for window boxes and hanging basket planters. The trailing types also tolerate a fair amount of shade. Flowers colors range from white through pastel shades of pink to red and purple.
Martha Washington or Regal: Large frilly flowers make these geraniums very special. They bloom in white and vivid colors such as orange, purple, red and burgundy. Regals thrive in part shade and can grow up to 4 feet tall.
Scented geraniums: These types that are gown primarily for their aromatic leaves with scents such as citrus, apple, rose, pineapple, chocolate or mint, to name a few. These plants have smaller, less showy flowers than the other types. Citrus-scented cultivars, such as ‘Citronella’ are sold as mosquito repellent plants, although they are not very effective this purpose.
Other types of geraniums: There are dwarf types and a group known as stellars, which have star-shaped flowers and notched leaves. The award-winning ‘Vancouver Centennial’ is one of the best known stellars.
I have not ordered plants from this nursery, so am not making a recommendation to purchase from them, but the web site, http://www. holtgeraniums.com is a good place to view the multitude available to the grower.
Pest problems are minimal with geraniums. Always keep fading flower stalks removed to reduce botrytis, which can be a problem during wet seasons. Proper plant spacing will also help to minimize this problem. Bacterial blight can be a serious problem -- usually evidenced when the plant or single leaves wilt for no apparent reason. Infected plans wild most readily under 70 to 80 degrees F. No sprays are available and the plant should be removed from the site immediately.
Although they can weather a light frost, geraniums love to bask in warm-weather. Most types do best in full sun, (at least 6 hours per day). If the weather is very hot, with many days over 90 degrees, your geraniums would appreciate being in partial shade. Many geraniums do quite well in part shade, but flowering will not be as prolific. These plants like rich soil that is well drained. Add compost to your soil for an added boost. Potting mix in pots works well, also.
Geraniums are heavy feeders. Give them fertilizer every two weeks or once a month at the very least. Use balanced, water-soluble fertilizer. Regular fertilizing is especially important for container-grown plants.
Water your plants thoroughly, but let the soil dry between waterings. Check containers during hot summer weather. If it is dry two inches down or more, it’s time to water.
Leaves do die and turn brown for a number of reasons, mostly because geraniums are quite sensitive to fungal disease from excess moisture and humidity. Keep your plants looking their best by deadheading them and removing dried or discolored leaves. Your geraniums will reward you by looking great all season.
So if you are one of those people who can “only grow geraniums,” you now know you have bragging rights and can hold your head high.
- Cheryl Potts

Espalier apple trees

About five years ago, my husband and I were discussing adding an apple tree to our small residential back yard.
Since we both love apples, we needed to decide what type of apple we liked best and where in our small yard we had room to plant it. We had two cherry trees and two peach trees planted already. The decision of what type of apple to choose was split. My husband loves Gala apples and I prefer Fujis. We solved that issue by choosing one of each.
Where to plant was another big issue. We hardly had space for one tree, much less two trees. We have this family mantra “where there’s a will, there’s a way” and so we thought long and hard about a remedy to this dilemma.
The answer was staring us in the face. We didn’t need to plant in the middle of the yard, but in the back of the vegetable garden against the fence. This type of planting is called “espalier” and means trained to grow flat against a wall or fence in a symmetrical pattern.
This technique was developed in the 16th century, out of the practical need for growing fruit in such marginal climates as northern France and southern England. The early French and English discovered if they bent apple tree branches horizontally they could direct energy away from vigorous vertical growth and into producing spurs (stubby lateral branches that flower and produce fruit). In addition, this would create a favorable microclimate in which the wall radiated heat and provided shelter. As they do today, many growers kept the trees dwarfed for ease of management.
We were both novices in our knowledge of this technique and what it took to grow and manage such a planting. We began reading books and searching the Internet for information on how to begin training fruit trees into horizontal branching. From what we read, it did not seem difficult and we were encouraged to give this method a try. The trees would not take a lot of space as they would be trained to hug the fence. In fact, they were quite architectural in the photos we collected.
We also learned it is wise to choose tree varieties that will pollinate each other and if you order from a reputable nursery, they will recommend compatible pollinators. We were told you can grow these trees against any supportive structure and they are a natural living shield to hide unattractive walls, fencing or compost bins.
Espalier trees produce more fruit per foot than do ordinary fruit trees. We traveled to three different nurseries asking questions and checking their containers with dwarf plants espaliered against wooden trellises. We saw fruit trees such as pear, Asian pear, apple, plum, pomegranate and dwarf citrus as well as ornamental plants such as camellias planted in the espaliered style.
Two dwarf trees were ordered through our favorite tree nursery, one a “Grand” Gala and the other a “Red” Fuji. We were so excited when they arrived, although the trunks were very small in diameter. They were planted 10 feet apart, and 8 inches away from the fence. Guide wire was run horizontally along the fence about 2 feet apart and secured to the posts with I-bolts.
Only the growth on the right and left side of the trunk was allowed to grow (side branches); all other growth was removed. As the branches grew horizontally, they were tied to the guide wires. As more branches grew, more guide wires were added. When the trees reached the top of the fence, their tops were trimmed. Over the years, both trees have thrived even though they get “pruned” and shaped often. They are fertilized yearly with fruit tree stakes, so both remain healthy and dark green.
Our vegetable garden has been planted each year, and often tomato plants tower over and obscure the two apple trees without any adverse problems. By this, I mean we have not found any tomato hornworms on either tree. Actually, we have had few, if any tomato worms on our tomatoes over the years.
One day we discovered a white cottony looking material hanging off the branches of the “Red” Fuji. Doing some research, we discovered the culprit was the woolly apple aphid, (Eriosoma lanigerum). This was not allowed on our revered apple tree. I removed as much of the cottony material as possible with dampened paper towels, then blasted the affected branch with a swift spray of water for three mornings and no more woolly apple aphids have been seen.
You cannot imagine how excited we were this spring when we saw our first apples on these uniquely shaped trees. We were wondering when (and if) we would ever be eating apples off our own trees or if we would be traveling to Apple Hill in Camino or the farmers market to purchase them.
At the end of July we picked our first Gala. It was fabulous! In fact it was the best Gala apple we had ever eaten. We invited family and friends over to “sample” our first harvest and they agreed it was a delicious apple and the best they had tasted.
Although there were only seven Galas this year, we have savored and enjoyed each one. Next year the harvest should triple. The “Red” Fuji fruit is not quite ready, but there are about 20 apples this year and we anxiously await their ripening.
The best thing about these trees, besides the delicious fruit is the fact the trees take so little space in the garden and they look like a beautiful garden focal point; especially during the dormant season of winter when the unusual branching patterns are revealed and again in the spring when the apple blossoms in varying shades of white and pink cover the branches.
-- Sharon Rico