Mother Nature's Backyard - A Water-wise Garden: Plant of the Month (September) : Lilac (Cedros Island) Verbena

Lilac (Cedros Island) Verbena (Verbena lilacena) - in container on porch
Mother Nature's Backyard

In September, the orange-brown seed heads of the Buckwheats provide a colorful backdrop for other late summer bloomers. One of the prettiest of ‘the others’ – which is blooming right now on our back porch – is the Lilac verbena, Verbena lilacena (pronounced ver-BEE-nuh lie-luh-SEE-nuh)

Plants know no political borders. In fact, the ‘California Floristic Province’ (the area west of the Sierra Nevada Range in California) includes parts of Baja California, Mexico. We’ve spoken before about the interesting connections between our Channel islands and those off Baja California (http://mother-natures-backyard.blogspot.com/2014/07/plant-of-month-july-guadalupe-island.html).

Because plants of the Baja Peninsula share not only climate, but also a geologic and botanic history, many Southern California native plant nurseries sell Northern Baja plants. These species often grow well in western Los Angeles County and add accents not available in locally native species. One such plant is the Lilac or Cedros Island verbena.

Lilac verbena hails from Cedros Island, off the coast of Baja. The island, which is well known to sport fishermen, is located about 62 miles (100 kilometers) west of Ensenada, Mexico, in the Pacific Ocean. Cedros Island, or Isla de Cedros ("island of cedars"), is home to a number of unique plant and animal species, some of which are endemic (like Verbena lilacena). To learn more about Cedros Island see references 1-3, below.

Lilac (Cedros Island) Verbena (Verbena lilacena) - in glazed
pot. Greenhouse, CSU Dominguez Hills

Lilac verbena naturally grows in sandy washes, canyons, slopes, cliffs and hillsides. It’s a mounded, evergreen sub-shrub that’s 2-3 ft. (about ½ to one meter) tall and 3-4 feet wide at maturity. In most gardens (with occasional water) the plant is evergreen; in a very dry garden, some leaves may be lost in the dry season (summer/fall).

Lilac (Cedros Island) Verbena (Verbena lilacena) in sunny location
Native Plant Garden, Madrona Marsh Nature Center, Torrance CA

The plant appears delicate, with numerous thin stems which are surprisingly stiff. The branch tips are herbaceous; the lower parts of branches become woody with age. Plants grown in part-shade are more rangy; those grown in full sun are naturally more compact (see above).

Foliage plays an important role in California native gardens. Foliage colors, shapes and scents provide the contrasts that define mediterranean climate gardens. Veteran Southern California gardeners know the trick of pairing lush, green plants with the soft gray- and blue-green foliage common in the Coastal Sage Scrub plants. The contrast is nothing short of magical! The problem is finding smaller shrubs that are both drought tolerant and vivid green. Lilac verbena is one such plant.

Lilac (Cedros Island) Verbena (Verbena lilacena) - lacy foliage

In fact, foliage is one of Verbena lilacena’s strong points. The color ranges from medium green to almost blue-green, depending on site characteristics. The leaves are highly incised, giving a lacy appearance to the foliage. In fact, Lilac verbena looks like a traditional garden plant; that’s probably one reason it’s become so popular with water-wise gardeners.

Lilac (Cedros Island) Verbena (Verbena lilacena),
Flowering plant

As if the foliage isn’t enough, Verbena lilacena has pretty flowers and a growing season that spans much of the year in our area. In hot, inland areas, plants seems to flower less in the hottest months. But plants can be covered in blooms from spring well into fall. The secret to a long blooming season is simple: deadhead (remove) the spent flowering stalks.

Lilac (Cedros Island) Verbena (Verbena lilacena).
Close-up of flowers

The flowers themselves are small – perhaps 1/3 of an inch (less than 1 cm) across. They have five notched petals and are relatively simple. The flowers grow along flowering stalks densely packed with flowers (see above). The flowers open serially, from bottom to top, providing a long bloom season.

In the most common cultivar, Verbena lilacena ‘De La Mina’, the flowers are medium purple (the straight species has paler purple flowers). In the cultivar ‘Paseo Rancho’, the flowers are pastel pink. All are strikingly pretty and attract a wide range of pollinators, from butterflies to pollinator flies. The flowers have a very sweet aroma; particularly noticeable on days with higher humidity.

Lilac (Cedros Island) Verbena (Verbena lilacena) 'De La Mina'

The cultivar Verbena lilacena ‘De La Mina’, which is readily available at native plant and other nurseries offering water-wise plants, was collected by Carol Bornstein on Cedros Island. It was introduced into the horticultural trade by the Santa Barbara Botanic Garden [4]. ‘Paseo Rancho’, which is less readily available currently, is slightly larger and was introduced by Rancho Santa Ana Botanic Garden [5].

Lilac verbena does well in many local gardens. It prefers a well-drained, sandy soil, but can be grown in clays. If your soil has questionable drainage, try planting it on a slope or on a small berm.

Lilac (Cedros Island) Verbena (Verbena lilacena) - El Rincon
Native Plant Garden, South Coast Botanic Garden

While often grown in full sun, Verbena lilacena may do better with some afternoon shade in hot, inland gardens. But this is not a plant for shady places – it really does need some sun to bloom well.

Lilac verbena is quite tolerant of a wide range of garden water regimes. It prefers a monthly deep watering in summer; that’s similar to conditions in the wild. But it can take even more frequent summer water, provided soils are well-drained. Be careful not to over-do with overhead watering during warm weather, as powdery mildew can be a problem. Watch for snails and slugs, which can eat young foliage.

Lilac (Cedros Island) Verbena (Verbena lilacena)
Well-pruned specimen, Native Plant Garden,
Madrona Marsh Nature Center, Torrance CA

Lilac verbena does require a little pruning to look good. Deadhead the flowering stalks regularly for best bloom. And cut back branches by 1/3 each fall to create a full, mounded shape. Wait until the weather cools down before pruning. The pruning doesn’t hurt the plant. In fact, it simulates ‘natural pruning’ by animals.

Lilac (Cedros Island) Verbena (Verbena lilacena) provides
color and contrast. Madrona Marsh Nature Center,
Torrance CA

Lilac verbena can be a welcome addition to many local gardens. It’s water-wise and of a size that can be accommodated by even a small garden. If needed, it can even do well in a container or large hanging basket. The green foliage creates a green oasis in the summer-fall garden. It is a great plant for providing contrasts.

Lilac (Cedros Island) Verbena (Verbena lilacena) contrasts
nicely with salmon-colored wall

This is one of our favorites for floral scent. Plant it where you can enjoy the sweetness as you walk past. While not a super-star like the Buckwheats, Verbena lilacena attracts enough insects to warrant a place in the habitat garden. And if you love those rare, unusual native plants, this is one of those.

In short, Verbena lilacena is an attractive, useful plant. It does well in local gardens with very little care and it is water-wise (ever so important these days). So consider purchasing a Lilac verbena at the up-coming native plant sales.