Tom Karwin, on gardening | In Bloom – Santa Cruz Sentinel


Take care of your garden

Spring is here! Its grand entrance comes this year with a heat wave that encourages flowering. While several plants in my garden are celebrating the season, some seem a bit slow to show their colors. This delay could be a symptom of our persistent dryness.

Today’s column features a selection of favorite plants, some already in bloom and others in photos taken in mid-March a few years ago, showing their near future.

White cistus (Cistus ladanifer x palhinhae ‘White’). This cultivar grows up to 8 feet tall with narrow green aromatic leaves and, in the spring, produces a profusion of 4-inch-wide pure white flowers that bees welcome. The genus Cistus, native to the Mediterranean region, includes 25 species and many hybrids. Plants are divided into two beaded groups on flower colors: the purple-pink clade and the white or whitish-pink clade. Some varieties of Cistus have flowers with colored spots. The hybrid in my garden is said to have been created by Collingwood Ingram (1880-1981) and won the Royal Horticultural Society’s Award of Merit in 1967.

Wonga Wonga Vine (Pandorea pandorana ‘Snowbells’). This woody climbing vine can reach 20 feet tall and 10 feet wide, with enough support. My plant is growing on a typical 6ft high fence topped with a trellis so it can’t grow to its full height. It produces a large number of flowers, so a 20-foot-tall specimen would look spectacular. Other varieties include the yellow-flowered ‘Golden Showers’ and the dewy ‘Ruby Belle’. This plant is native to Australia and parts of the Pacific Southwest region.

Oregon grape (Mahonia pinnata). This evergreen shrub grows widely along the Pacific Coast from Oregon to Baja. Its ancient botanical name was M. aquifolium, but it has long been known as the Oregon grape. It is also called “hollyleaf barberry”, referring to its waxy green leaves that look like holly leaves. In 1899, Oregon designated the delicate yellow flowers of this plant as the official state flower.

Common Lilac (Syringa vulgaris ‘California Rose’). The lilac, native to the Balkan Peninsula, widely appreciated for its fragrance, is generally considered in America to be an East Coast plant because it requires a period of coolness. I remember enjoying Lilacs when I was young in Connecticut. Several decades ago, this plant became available in more temperate climates like the Mediterranean Bay Area with the development in Southern California of warm weather varieties known as Descanso hybrids. Cultivars include ‘Angel White’, ‘Blue Boy’, ‘Dark Night’, ‘Chiffon’, ‘California Rose’ and ‘Lavender Lady’. Compared to the species, Descanso hybrids lose some of their reputedly strong (but still very pleasant) fragrance and grow shorter (but 6-10 feet tall is suitable for most gardens).

Advance your knowledge

Upcoming garden webinars and online video recordings.

The UC Santa Cruz Center for Agroecology will present the “Gopher Control in the Home Garden and Small Farm” webinars, 5-6:30 p.m. on April 5. The presenter, Thomas Wittman, is the founder and owner of Gophers Limited, which is “dedicated to humane resolution of pest conflict without the use of poisons.” A friend of UCSC Farm & Garden and the Arboretum & Botanic Garden, Wittman has shared his knowledge of gopher control with several local gardening groups. This event has a participation fee of just $5, which could help viewers protect their precious garden plants from gopher attacks. To register, go to and search for “gopher”.

The UC Santa Cruz Center for Agroecology has produced numerous short video recordings on a range of home gardening topics. For free access to this impressive video library, go to, pull down the Resources menu, and click Instructional Videos. This will open a webpage which lists titles under selected headings and provides a link to the Centre’s dedicated YouTube channel, where many additional video recordings are available. The string can be browsed or searched for topics of individual interest, for example, “pruning”, “seed starting”, “vegetables”, etc.

The American Horticultural Society will present the final webinar in its series, “Conversations with Great American Gardeners,” at 4 p.m. on April 21. This episode will feature famed horticulturist Shane Smith, founder and director emeritus of the award-winning Cheyenne Botanic Garden. To learn more, and to register for this paid event, go to, navigate to “Upcoming AHS Events” and scroll down to the list for the conversation with Shane Smith.

The Public Broadcasting System has launched “GardenFit,” a new series of video programs to “learn how to take care of your body while taking care of your garden with expert gardener Madeline Hooper and personal trainer Jeff Hughes.” Visit gardens across America and learn gardening tips and techniques to avoid stress and injury. These programs will air on PBS stations and stream online for viewing at convenient times. Gardeners of all ages could always learn more about physical preparation for effective and enjoyable gardening. Visit for more information.

The Cornell Lab of Ornithology has released its Bird Academy, a library of recorded video presentations about — you guessed it — birds. A recently recorded webinar titled “Preparing for Spring Birdwatching” features birder Dr. Kevin McGowan, answering burning questions about birds as we prepare for spring birdwatching. This hour-long event and several other recorded videos are available for free at

For a deeper “dive” into birding, consider Bird Academy’s Joy of Birding, a self-paced online course “designed to help bird enthusiasts get started on their birding journeys. Find out how to find more birds in your area, how to get the most out of binoculars, learn essential bird identification tips and techniques, and more.This online course is available at a deeply discounted price only until April 2. For more information, visit

Enrich your gardening days

Spring is here and it’s time to enjoy the weather, marvel as established plants sprout new leaves and buds, and satisfy the seasonal urge to bring new plants into your garden.

Don’t forget to mark your calendar for the Monterey Bay Dahlia Society’s annual tuber sale on April 2 (more details in next week’s column.)

Persistent drought poses significant obstacles to successful gardening. While there are no easy answers to these challenges, we’ll review practical priorities in future articles. As always, your ideas are welcome!

Enjoy your garden!

Tom Karwin is past president of the Friends of the UC Santa Cruz Arboretum, the Monterey Bay Area Cactus & Succulent Society, and the Monterey Bay Iris Society, and UC Lifetime Master Gardener (certified 1999-2009). He is now a board member and garden coach for the Santa Cruz Hostel Society. To see daily photos of her garden, For information on gardening coaching and an archive of previous On Gardening columns, visit Contact him with comments or questions at [email protected]***


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