Native Plants: Blackberries: The good, bad and thorny

Analia Kamis Bertucci, Shasta Chapter of the California Native Plant Society Published 12:30 p.m. PT Jan. 5, 2017 636192255159153384-Photo-4.jpg (Photo: Courtesy of Jim Riley) CONNECTTWEETLINKEDINCOMMENTEMAILMORE The seasons mark the passing of the year for many, but for me they mark the anticipation of the next fruit collection. Late spring bears apricots and strawberries; summer peaches lead to autumn apples and pomegranates; winter sheds citrus. The summer months are a favorite for fruits and I have fond memories of picking blackberries to be made into tarts and pies, or enjoyed fresh off the vine. Once school was out, those hot and sunny afternoons were spent next to creeks, basking in the water and grazing on blackberries, taking care to avoid the prickles. It wouldn’t be until years later that I realized those juicy berries were from a plant that some consider a plague. As part of the rose family, Rosaceae, blackberries can literally be a thorn in one’s side. California’s native blackberry, Rubus ursinus, also known as Pacific blackberry, has been overtaken rapidly by the Himalayan blackberry, Rubus armeniacus. Despite its name, this introduced shrub is from western Europe and has made itself at home here; most of the blackberry encountered in Shasta County is non-native. Though it is unknown how the species was first brought to North America, it is likely it was a cultivar that escaped, as is the case with many well-established non-native flora. I have yet to encounter any native blackberry thickets in the area, and people familiar with the plant can recall only a few prominent patches located in remote areas. At first glance, the two plants look nearly the same, both with usually white flowers, and leaves with serrated edges sprouting along thorny stems. However, upon taking a closer look, you will notice the differences between the shapes of their leaves and the petals of their flowers. The robust blackberry plant spreads rapidly and can The robust blackberry plant spreads rapidly and can be found in abundance close to waterways. (Photo: Courtesy of Jean Pawek) The leaves of the Himalayan species are more cordate, or heart shaped, with more finely serrated edges than those of the Pacific variety, which has more grooves. The five petals of the Himalayan blackberry are generally fuller and wider than the Pacific blackberry, and the thorns are more abundant on the non-native. Though the blooming and fruiting periods of both plants overlap, the Himalayan starts later in April and fruiting can extend from July to September. Blackberry stems, known as canes, can grow upward to about 15 feet (4.6 meters), and trail across the ground up to 40 feet (12.2 meters). Drooping canes can root at the nodes when they touch the ground, making a nearly impenetrable wall of tangled thorns when grown out. While many plants lie dormant during the winter months, the Himalayan blackberry stands out like a giant mass of green and reddish leaves with its weaving, giant, thorny arms daring you to cross it. This is great for those smaller creatures seeking protection but, for the rest of us, it is a major deterrent to pass through. I have ripped many shirts (now designated “blackberry” attire) by reaching into the brambly thickets. The leaves and flower of the Himalayan blackberry, The leaves and flower of the Himalayan blackberry, Rubus armeniacus. Note how the leaves are fuller with a continuous serrated edge. (Photo: Courtesy of Stephen Sharnoff) Though the Himalayan blackberry is now considered to be a mainstay and a naturalized species, it still should be managed. Due to its robust nature, it grows large and spreads rapidly, shading out many other understory plants, such as saplings of Douglas fir and ponderosa pine. It can invade almost any open space, such as oak woodlands, meadows and roadsides, and it thrives in riparian areas or wetlands, decreasing ecological diversity. It can clog up water flows in creeks, which can cause major problems during heavy rain. If left alone, it can wreak havoc. The leaves and flower of California’s native blackberry, The leaves and flower of California’s native blackberry, Rubus ursinus, also known as Pacific blackberry. Note that the petals are more narrow interiorly, giving it a more spread-open appearance, and the leaves have pronounced serration along the edges compared to those of the non-native Himalayan blackberry. (Photo: Courtesy of Russell Huddleston) There are various control methods that can be used, from herbicides to grazing to trimming. Due to the plant’s proclivity for wetland and riparian areas, herbicides should be carefully used, especially when in close proximity to water. Grazing and trimming may not completely eradicate the plant since these methods do not stop the formation of adventitious roots; the plant can grow roots easily from its stems. Burning plant clippings and digging up the roots are tedious but probably the most effective method to control the plant. Dealing with the Himalayan blackberry is difficult from a physical and ethical point of view. The large mound of vines can appear quite pretty when the plant is in bloom, with all its white flowers set amidst the green foliage. It provides a feast of delicious fruit in the summer and it provides some habitat; however, it also disrupts the balance and function of the environment it occupies if left unchecked. Thickets that have been thinned can grow back with a vengeance if not maintained, preventing other plants from establishing and reducing the diversity of both flora and fauna. Attempts to control it may seem futile, but there is hope if regularly maintained. And, of course, there’s the bounty to collect in the late summer as reward for your work. Native Plants runs the first Saturday of the month in the Home & Garden Section. Articles are provided by members of the Shasta Chapter of the California Native Plant Society. For more, go towww.shastacnps.org. CONNECTTWEETLINKEDINCOMMENTEMAIL