This is the second of four articles describing plants and their care featured in the UC Master Gardeners of Napa County's low water, low maintenance area at the Las Flores Learning Garden.
Raywood ash
Raywood Ash,with the Latin name of Fraxinus oxycarpa (or angustifolia) 'Raywood,' reaches to a maximum height of 50 feet and a canopy width of 20-30 feet. With a lower trunk of a light gray rough bark and upper branches of smooth gray, this tree has the possibility of growing up to 24 inches in a year until its final height is reached. Raywood ash has spear-shaped, 3-4 inch leaves that turn a wonderful deep red in the fall and then drop in early winter. As with other deciduous trees, leaves are somewhat of a mess to clean up, but no other debris during the rest of the year, other than occasional small branches broken during heavy winds, are in evidence. It requires little or no pruning to shape as it grows. As safety first should always be observed, pruning of a full size Raywood ash may best be left to a professional. Considered to be smog tolerant and having roots that tend to be deep, these trees can be planted in a row at least 10 feet apart to create a screen. They are deer resistant and grow best in full sun or part shade. When stressed, these trees have some susceptibility to root rot, sooty mold, verticillium, beetle borers, scales and white fly, but are resistant to armillaria. Raywood ash is less drought tolerant than previously believed, so occasional deep watering during the drought season and pruning to thin canopies will help keep the tree healthy and avoid stress.
Crape myrtle
Crape Myrtle, Lagerstroemia indica seems to be ubiquitous in many landscape designs and a frequently seen street tree in our valley. The crape myrtle can be grown as a single trunk or multi-trunk tree or a bush. They reach a maximum height of 15 feet with a canopy width of 6-15 feet, depending on which form is desired. Multi-trunked trees can require some pruning and shaping. This maintenance can be accomplished without a professional as they are not that tall. The deciduous leaves are oval and bronze, purple or reddish. Myrtles come in a wide range of colors, including white, lilac, and purple, many shades of pink and different shades of red. Again, being deciduous means fall cleanup of leaves, but there are other litter issues with the crape myrtles, too. In spring, flowers fall and in fall fruit drops along with striking light green, pink or red brown bark that exfoliates regularly, exposing smooth bark underneath. All of this contributes to continuous cleanup needs. Crape myrtles, when stressed, have a susceptibility to sooty mold and aphids. On the plus side, these trees require little water once established, are deer resistant, attract birds and bees and are resistant to powdery mildew. These lovely little trees provide wonderful, continuous visual interest with their curving multiple trunks, lovely leaf and bark color and a bountiful colorful floral display each spring.
Arbutus flowers
Strawberry Madrone, Arbutus unedo is native to southern Europe and Ireland. These rounded or vase shaped trees have evergreen oblong shiny dark green leaves and colorful red-brown exfoliating bark. Arbutus can be grown as multi-trunked shrubs or tree form. The pink and white lantern shaped flowers are sprinkled all over the canopy of the tree or shrub and attract hummingbirds. The inch long rounded fruit is sparkly bright yellow and red dangle throughout the foliage. The fruit is edible to humans but mealy and bland in texture and somewhat messy, but wildlife like to eat it. Interestingly, flowers and fruit seem to be produced on a rotating basis all year in our area. Once established, trees grow to 35 feet tall and wide and require only occasional deep summer watering. These trees don't need pruning except to keep their height to your preference. Plant in full sun to part shade and in well-drained soil. Fertilizer isn't needed and the trees are reasonably pest free. Some possible problems might be anthracnose, phytophthora, root rot, rust, scale and thrips, but arbutus does have a resistance to armillaria. These trees make quite a statement in a row with their lovely shape, cool striated bark, pink/white flowers and red and yellow fruit.
Arbutus fruit
In conclusion, once established, these three trees require little water and maintenance. Additionally, each can be counted on to demonstrate visual interest at some point during the year.
The UC Master Gardeners and the City of Napa have joined in a partnership at the Las Flores Community Center where instructional events are planned for the last Saturday of the month through 2022. Topics will center on research-based horticultural and climate change issues by featuring water saving plants and soil care.
Next week, in the third installment of these articles, we will talk about the Yellow-twig dogwood, Loropetalum and Meyeri fern.
Napa Master Gardeners are available to answer garden questions by email: mastergardeners@countyofnapa.org. or phone at 707-253-4143. Volunteers will get back to you after they research answers to your questions.
Visit our website: napamg.ucanr.edu to find answers to all of your horticultural questions.
