Wheel of the Garden: August Blackberry

by Jenny Krueger

August greetings! Jenny Krueger here, Lead Gardener & Educator with the Anacortes Middle School Garden Project. Last spring, I enjoyed introducing students to seasonal foods with brief “Spotlight on a Plant” talks to open class. Now, I am pleased to expand these spotlights with a series of blog posts that I am calling The Wheel of the Garden.

Each month over the next year, I will share deep dives into a plant that is a seasonal touchstone for me in my garden and others on Fidalgo Island. These posts will explore botanical, horticultural, agricultural, ecological, nutritional, culinary, folkloric, and personal aspects of the marvelous beings that shout – or whisper – the turning of the year on this glacier-carved island of the Salish Sea.

For me, August is the month of Blackberry.

Juicy, thorny, aromatic, aggressive, nutritious, notoriously invasive. Blackberry holds paradox better than most plants I know. The blackberry that I am describing, of course, is Rubus armeniacus, the Himalayan blackberry. Though we do have the native trailing blackberry (R. ursinus) and the naturalized cut leaf blackberry (R. laciniatus), the Himalayan blackberry is so ubiquitous that most simply call it blackberry. I hardly need to describe its arching canes that can reach 15 feet high and 40 feet long, palmately compound leaves with 3 to 5 serrated leaflets, large clusters of white-to-pink flowers, and heavily hooked prickles, commonly described as thorns. In Washington state, even those who know only a handful of plants can recognize this semi-evergreen perennial shrub.

When considering a plant, it’s helpful to put it in the context of its botanical groups. The Rubus genus, part of the rose family (Rosacaeae), contains hundreds of species found around the world and collectively known as brambles. They all have the five-petaled, many-stamened flower of the rose family. The PNW native plants salmonberry (R. spectabilis), thimbleberry (R. nutkanis), and blue raspberry (R. leucodermis) are also part of Rubus, as are the cultivated plants raspberry, loganberry, tayberry, boysenberry, marionberry, and thornless blackberry (all of which are somewhere on a hybrid continuum between raspberry and blackberry). My mouth is watering just listing these luscious, aggregate fruits. 

Brambles are valuable for wildlife, providing food and habitat. I have seen a rabbit quickly disappearing into a blackberry thicket more often than anywhere else. That being said, the Himalayan blackberry is a Class C noxious weed in Washington. Some even call it the State Weed of Washington. Property owners are not required to remove it, yet I encourage anyone with Himalayan blackberry in their garden to carefully do so at first sight. In large properties, it can be thoughtfully managed for food production in the far reaches. However, unimpeded, it quickly forms enormous, impenetrable, razor-sharp thickets that can outcompete other species, injure the inattentive, and even swallow a small house. No joke, I’ve heard first-hand accounts of goats uncovering a neglected home from rambunctious blackberries.

Himalayan blackberry loves open, disturbed sites with adequate moisture. I remember as a child, growing up on clear-cut land in northeast Skagit County, there were blackberry brambles covering the steep ravine at the front of our yard – into which my brave brother once crawled to rescue our indoor cat! That incident reminds me of the Brothers Grimm tale “Little Briar Rose,” wherein the princess pricked her finger and fell into a deep sleep of a hundred years, during which time her castle was surrounded by a thorny hedge of briar, or brambles. 

The best way that I have found to weed out blackberry plants within a garden bed is to use loppers to cut large stems back to the root crown. Though I wear thick gloves and cover my arms, legs, ankles, and feet, I also use the loppers to “hold” and maneuver the thorny stems. It’s quite possible to get an infection from a deep puncture through gloves. Personally, I compost them municipally, as the stems can possibly reroot in a cold, home compost pile. They could also be burned, as appropriate. If it’s a big crown, a heavy mattock is the best tool for removing as much root as possible. If it’s just a sprout, I dig down with my hori hori, grasp it by the exposed (thornless) root, and yank. In a field setting, repeated mowing can help exhaust the roots. A friend has had success with repeated mowing followed by an extremely thick layer of arborist chips when beginning a new garden in a field previously claimed by blackberries. While the chips will likely not completely smother them, it does make the later weeding easier. 

As a note on our local Rubus species in general, I do remove uninvited trailing blackberry and blue raspberry (aka blackcap raspberry) when gardening for myself and clients, because they are ankle-catchers with poor garden manners. Thimbleberry is the least armed of all the local brambles, having only what my field botany professor described as “weak prickles.” This shrub’s large, velvety leaves and tasty berries would surely convince me to leave a well-placed volunteer, should I be so lucky, or consider purposefully planting one. As for salmonberry, it’s pretty in bloom but needs plenty of space. I would rather enjoy its magenta flowers on an early spring hike than in my garden.

For gardeners here on Fidalgo Island, the removal of blackberry plants happens throughout the year. Last December, I was helping another friend with a blackberry intervention in her two-year-old native plant hedgerow. I did as previously described, thinking I was well ahead of the next season’s exponential growth. My pulse quickened when I noticed how large the buds had already swollen. 

But in August? The flavor of the game changes. The berries have turned, so to speak. Now, I aim to prevent more seeds from sprouting by picking and enjoying the supremely delicious fruit. There will still be uncountable numbers of seeds ripening over the next two months, and yet … my heart softens as the plump, fragrant berry melts in my mouth. Luckily, the Anacortes Parks Department chooses to control the blackberries in our parks and forestlands manually, without spraying pesticides, allowing folks to safely pick berries in these public areas for consumption. It goes without saying, but I will anyway, that you must be sure to pick berries that have not been sprayed, and with permission.

And pick we do! Perhaps it’s in my half-Finnish blood: I love to forage berries. My 9-year-old, Leo, has been prompting summer walks in “the nearby woods,” to keep a close eye on the berries forming. In August, a ramble there offers buckets of berries – if I can outpace the rate at which he eats them. I look for berries that are completely black and glossy; a dull color often signals over-ripeness. Purple-stained fingertips tell the tale of a happy afternoon spent with loved ones.

The berries are delicious, nutritious, and so quintessentially PNW that I have a cookbook titled Dungeness Crabs and Blackberry Cobblers: The Northwest Heritage Cookbook. According to verywellfit.com, they are a “fiber-rich source of nutrition with plenty of vitamin K, potassium, magnesium, and vitamin C. They also offer potent antioxidants and are naturally low in calories and fat.” Blackberries freeze well; just be sure to flash-freeze in a single layer on a sheet pan before putting in an airtight freezer container for storage. There’s also plenty of natural pectin and acidity in the fruit to easily gel jam without commercial pectin. Ashley Adamant's recipe, from the blog Practical Self Reliance, is the one I’ve used with success – with lemon juice and a 2:1 fruit to sugar ratio. Blackberry Jam is the best jam, in my humble opinion.

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What’s your favorite way to eat blackberries? In smoothies, crisp, overnight oats, pie, kombucha, yogurt, or what?

Here’s my favorite recipe, adapted to my tastes from the blog “Eating Richly.” It’s wonderful any time of the year, but I especially love to bake it in the winter when I need to warm my bones and recall the majesty of August: the golden tones of light and leaf, the abundant harvest, the sun-kissed swim at the lake with a bowl of blackberries.

Blackberry Walnut Baked Oatmeal 

Ingredients

• 3 Tbsp butter

• 1 ½  cups rolled oats

• 1 tsp ground cinnamon

• 1 tsp ground ginger

• ½ tsp baking powder

• ¼ tsp salt

• 1 ½  cups whole milk (or dairy-free substitute) 

• ¼ cup real maple syrup (or honey – this is a great way to use up crystallized honey) 

• 1 egg yolk

• Splash of vanilla extract

• 2 + cups frozen blackberries 

• ¼ + cup chopped walnuts

  
  

Instructions

1. Preheat the oven to 375 degrees F.

2. Use 1 Tbsp of butter to generously grease the bottoms and sides of an 8 x 8 square baking dish or equivalent. 

3. Melt the remaining 2 Tbsp of butter and remove from heat to cool slightly.

4. Mix the dry ingredients in a bowl (oats, spices, baking powder, and salt).

5. Mix the wet ingredients in another bowl (melted butter, milk, maple syrup, egg yolk, and vanilla extract). If using up crystallized honey rather than syrup, roughly mix it with the frozen berries in the next step instead of with the wet ingredients.

6. Cover the bottom of the greased baking dish with frozen berries (and frozen diced apples, if using).

7. Cover the berries with the dry ingredients.

8. Slowly pour the wet ingredients over everything, tilting the pan as needed to ensure all the oats are moistened.

9. Scatter the rest of the berries and the walnuts on top and gently pat them into the oats so that they are half-submerged.

10. Bake uncovered for about 40 minutes, until golden and the oats have set.

11. Serve with an extra drizzle of honey if desired.

This recipe serves 6. It can be easily doubled and baked in a 9 x 13 baking dish for a larger crowd. Leftovers keep well for several days and can be reheated in the oven in a covered dish at 350 degrees F for 20-30 mins or until hot.