By Yvonne Rasmussen, UC Master Gardener of Napa County
What flowers in the dead of winter in Napa County? With few pollinators active then, it's not a great time to have flowers that need pollination. Also, the weather is dicey. It could be cold or icy or raining and blowing. But surprisingly, many plants do bloom between late fall and very early spring. So with a little planning. you can have flowers in your winter garden and fresh-cut flowers to bring indoors.
Camellias, cyclamen, primroses and pansies are all blooming in nurseries now. But don't be fooled. Some of these plants have been forced into bloom using light or greenhouse conditions. They may not repeat that winter performance once naturalized in your garden.
The camellia shrub's glossy evergreen leaves provide a wonderful contrast to its flowers, which bloom in various shades of pink, red and white. The flowers come in many color patterns and bloom times and the shrubs take a variety of shapes. According to the American Camellia Society, there are more than 4000 cultivars. You can search the society's website for a camellia that suits you, basing your search on up to 14 plant characteristics.
To find other hardy winter-blooming shrubs with low water needs, I turned to the UC Davis Arboretum All Star listing and the Sacramento Master Gardener's website. The Arboretum All Star plants have been grown and evaluated at the UC Davis Arboretum and are designated as All Stars based on their ease of care and low water needs. Many are California natives but others are from locations around the world that have similar climates and seasonal drought.
Plants from areas that have a Mediterranean-type climate like ours, such as Australia, New Zealand and South Africa, often do well here. When choosing plants from these lists, pay attention to the specific cultivar or variety. The variety may have been developed for specific conditions, such as low water availability, low light or heavy soil. Or it may have other characteristics that distinguish it from the norm, such as smaller size or early bloom time.
Among the California native shrubs that bloom in winter, consider manzanita. It produces its small pink urn-shaped flowers in late winter through early spring. Bees love them. Mahonia is another possibility. It offers large sprays of small aromatic yellow flowers from fall through early winter. Witch hazel blooms from October through March and can tolerate temperatures in the single digits.
For low-growing plants in shade, consider hellebore, also known as Lenten rose, or Algerian iris (Iris ungulicuarus). Both bloom from late fall through early spring. Algerian iris make wonderful cut flowers for bringing indoors.
For bedding plants, you could choose primroses, which bloom in many colors. Make sure they are English primroses if you want winter bloom.
Cyclamen is another great bedding plant that flowers in many shades of pink, red and white. The plant themselves come in various sizes with leaves that may be variegated, rufflee or plain. If you're looking for annuals, viola and pansies bloom all winter in a variety of colors.
Last but not least, there are many bulbs, corms and rhizomes that will bloom from winter through spring and into summer. Many of these can naturalize given some summer shade under deciduous trees or shrubs. They provide a surprise in the garden each winter and spring when they reappear after being dormant all summer. Bright blue-purple crocus, white narcissus and yellow daffodils can create swaths of color over long periods if you plan well.
Winter does not have to be a dull, dreary, colorless time in the garden. Many easy-care plants can bring you flowers even in the dead of winter.
Library Talk: UC Master Gardeners of Napa County will host a free talk via Zoom on Thursday, January 6, from 7 pm to 8 pm, on “Introduction to Espalier.” The espalier technique is a great way to grow fruit in limited space and makes care and harvesting easier. Learn how to plan, plant and maintain an espaliered fruit tree in your landscape. Register at http://ucanr.edu/2022JanEspalier.
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- Author: Alison Collin
Mahonias belong to a genus of shrubs which are closely related to barberries (Berberis). They originate from many different areas of the world, including the Pacific Northwest and the Southwestern deserts of the United States, while many with the most striking forms come from China and Japan.
They are mainly characterized by evergreen, spiny pinnate leaves which are leathery in texture and sometimes glossy so that they resemble holly. They are valued for their yellow flowers which are produced in either rounded clusters or elongated spikes in late winter and early spring when little else is blooming, and these are beloved by honey bees, so provide some welcome early food whenever the sun is warm enough for bees to fly.
In the garden they can cope with a variety of different exposures depending on the species, but most prefer shade, or shelter from hot afternoon sun in desert areas. Many will even grow against a north facing wall. Heights also vary by species, some being creeping while others can grow to 12 ft., although that height would only be reached under optimum conditions. Water requirements also vary and I have found that although many originally come from the Pacific Northwest they are surprisingly tolerant of dry shade. In general the Mahonias are considered easy to grow although they may take a little while to settle in after transplanting.
For many years I avoided growing these plants because, although the leaves were quite handsome, the actual plants that I saw in peoples' gardens tended to look rangy but I have since discovered that with occasional, judicious pruning they can be quite handsome, and since they do grow in the high desert, and are generally ignored by deer they have much to recommend them.
Last year I planted a variety of Mahonia x media 'Lionel Fortescue' on a north facing wall, and not only did it come through the winter with flying colors, flowering early as promised in mid February, but it also coped with brief blasts of afternoon sun coming from the west without any damage to its leaves. It has a strong upright habit which promises to be a striking focal point in the border.
The more commonly planted Mahonia aquifolium, or Oregon Grape is generally lower growing and spreads by underground stems. It may grow to 5ft. high under ideal conditions, but can also be used as a ground cover if tall stems are removed at the base. Often new growth is reddish in color.
The desert native, Mahonia fremontii is an upright, multi-stemmed shrub with very spiny gray-green leaves and short spikes of yellow flowers in late spring. It is generally considered hardy in USDA Zone 7, although it comes from the Southwestern desert. It requires very little water.
Another popular hybrid is Mahonia "Skylark" which grows to 5ft tall, has reddish new leaves which then take on a purple hue in winter. The berries are dark purple. It requires little water.
There are many other varieties of Mahonia, so whether you are looking for a low-growing foundation shrub for an informal woodland setting, or a bold focal point, a scan of specialist nurseries should provide you with a plant to fit your needs.
More information at:
sonomamg.ucanr.edu/Garden_Sense_Master/GardenSense_Plants/?uid=93&ds...
oregonstate.edu/dept/ldplants/mapin.htm