flowering quince (Cydonia sp.)

rockspray cotoneaster (Cotoneaster microphyllus)

‘Iceberg’ roses and their fruits (rose hips)

I have a volunteer cotoneaster growing in my garden and I cannot decide whether to remove it or just let it be.
A volunteer is a plant that sprouts from a seed you never planted. It comes from a seed that blew into your garden with the wind or was excreted by a bird or deposited there by a squirrel.
Other volunteers that have germinated in my garden include Brazilian pepper tree (Schinus terebinthifolius), edible fig (Ficus carica), evergreen ash (Fraxinus uhdei), California black walnut (Juglans californica), California fan palm (Washingtonia filifera), Chinese elm (Ulmus parvifolia), and carrotwood (Cupaniopsis anacardioides). Whenever a volunteer sprouts in your garden, it is a sure sign that your garden’s conditions are perfect for its development.
Cotoneaster (kuh-toe-nee-ASS-ter) is a plant for all seasons and has always been one of my favorites. I have never seen it do anything but thrive, and with a minimum of water to boot. Although a very leafy plant, I have never seen any sign of wilt, disease or insect pests. If plants could talk, cotoneaster would never complain.
Cotoneaster is a plant for all four seasons. It is covered with white apple blossom flowers in the spring; shows off its bright red fruit in late summer, fall and winter; and displays dense, stem-hugging foliage all year long.
There is much to learn from this plant. Despite having minimal needs, it gives nonstop and has a pleasant demeanor at all times. Or, perhaps you could say that because it has minimal needs, it is always giving and smiling and has no sense of entitlement.
Cotoneaster is derived from two Greek words: cotoneum, meaning quince, and aster, which means similar. (Just for the record, aster in Latin means star. Asteraceae is the Latin word for all members of the daisy family and refers to their starlike flowers.)
Cotoneaster foliage resembles that of the quince. Its fruits will remind you of tiny red apples. It is in the rose family, which includes apple, pear, peach, apricot, plum, almond, cherry and quince. Cotoneaster species are highly variable and there is a species for you, whatever your garden needs might be.
There are giant cotoneasters (Cotoneaster lacteus) that grow into fountainesque shrubs over 8 feet tall and may serve as a screen or tall hedge; and ground-hugging cotoneaster mats (Cotoneaster dammeri).
I am especially partial to a species that grows into a low hedge. It is known as rockspray cotoneaster (Cotoneaster microphyllus), with leaves that are 1/3-inch long and proportional, complimentary, sessile fruit that grows all along its shoots and is abundantly visible, in vivid red, even when shearing is performed on a regular basis.
Besides cotoneaster, the rose family is also home to red-tip photinia, pyracantha and the California native toyon (Heteromeles arbutifolia), three landscape ornamentals with fruit similar to that of cotoneaster.
There is a significant disadvantage, however, in growing these other ornamentals due to their susceptibility to fire blight, a condition that blackens leaves on shoot terminals. Fire blight is caused by a bacteria that infects many plants in the rose family, including ornamental pear trees and India hawthorn, through their flowers.
Red-tip photinia, that well-known shrub whose flushes of new leafy growth are a brilliant scarlet red, is also victimized by Entomosporium leaf spot, a fungus disease that can significantly disfigure the plants. This disease has become so widespread that I would not advise anyone to plant photinia at this time.
India hawthorn (Rhaphiolepis species) is also susceptible to this fungus where air circulation is restricted. Droplets of water or dew, resting on leaves for even a short while, may invite germination of fungal spores. That’s why you sometimes see gardeners hosing down their roses in the early morning, a procedure that knocks fungal spores off the plant.
While I have frequently seen all of the above plants stricken with one disease or another, every cotoneaster plant I have ever seen was in perfect health.
There is an ornamental quince I have been watching for a number of years that generally blooms in late February. This year, it has flowered a month early. Early flowering could be explained by the warmer than average temperatures we have experienced, the lack of significant rainfall, or both. Any sort of stress in a plant’s environment can stimulate flowering.
Yet, although warmer than usual temperatures may bring some plants into flower sooner than expected, it may delay or inhibit flowering altogether in other species. Certain peaches and apples, for example, may only flower when the winter is cold; and cherries, no matter how cold the Valley winter may be, will seldom, if ever, flower here.
Ornamental pears (Pyrus kawakamii) are also in bloom. Their loud clouds of white blossoms, together with their small stature, not exceeding 20 feet in height, and glossy semi-evergreen foliage, have bolstered their reputation as the most manageable of trees, with the possible exception of purple-leaf plums, which are of comparable size.
Alas, both the ornamental pear and the purple leaf plum are short-lived and, while providing beauty, do not give enough shade to sit or picnic under on a summer’s afternoon.
Tip of the week
Rose seeds form in hips, those orange to reddish-orange fruits that develop where faded roses are not removed from the plant. In order for the seeds to fully ripen, hips must be left on the rose bush for at least four months.
Preferably, you will harvest hips in the winter since a spell of cold ensures their proper development.
Once this time requirement has been met, detach the hips and cut them in half with a bread knife. Remove the seeds and separate them from the pulp under running water and then soak them in water overnight. Seeds that sink to the bottom of a water glass are more likely to germinate than those that float on the top.
Place clean rose seeds in damp peat moss and refrigerate for two months. After moist refrigeration, also known as stratification, place seeds at a depth of 1/2-inch in a tray containing sand, vermiculite or an even mixture of the two. Place the tray in good light and your rose seeds should germinate within two months, some more quickly than others.
If you want to make rose hybrids of known parentage, do so with the first roses of spring, when the identity of the parents is not in doubt.