Pennsylvania blackberry, a bramble native to North America, features rugged canes clad with fine thorns, enabling it to thrive in dense thickets. Its compound leaves change from green to warm autumnal hues, and it bears white flowers that give way to tart, red-to-black fruit. This resilience and adaptive fruiting strategy showcase an evolutionary finesetuned with its forest and field habitats.
I. Appearance and Characteristics
Rubus pensilvanicus, known commonly as Pennsylvania blackberry, is a prickly bramble native to eastern and central North America from Newfoundland south to Georgia, west as far as Ontario, Minnesota, Nebraska, and Arkansas. The species is also established as a naturalized plant in California.
Rubus pensilvanicus is also known as Rubus abactus a synonym. In 1804 R. pensilvanicus was described by Jean Louis Marie Poiret in Encyclopedie Methodique: Botanique. Some common names include: Blackberry, Dewberry, Pennsylvania Blackberry.
The genetics of Rubus are extremely complex, making it difficult to separate the group into species. What some authors lump together as R. pensilvanicus, other authors split into as many as 50 or 60 species.
Rubus pensilvanicus, finds its home in states including Pennsylvania and New York, as well as, a few patches of distribution in the Midwest. This perennial, is a member of the Rubus genus with raspberries and blackberries, stands tall with its thorny canes that deter thin skinned humans and animals from trampling through it. The name “pensilvanicus” alludes to a strong presence in the Keystone State, Pennsylvania.
Rubus pensilvanicus is a 8 foot tall perennial bramble armed with sharp prickles along its stems. The fruit is black to purple in color, fleshy in texture, and edible to humans and wildlife.
The leaf structure of Rubus pensilvanicus is characterized by compound leaves, composed of two or more discrete leaflets. Along the stem, there is a single leaf per node. The leaf blade edges are serrated, featuring distinct teeth. In terms of leaf duration, the leaves either drop off during winter or wither but persist on the plant. Notably, the plant is armed with spines, prickles, or thorns.
The dimensions of the leaf blade range from 110 to 220 mm in both length and width. Each leaf possesses a leaf stalk. The fruit, it is of a fleshy nature. The bark of the mature plant is thin and smooth, while the twigs exhibit a winter coloration in shades of brown or gray. The winter buds are characterized by three or more scales, overlapping like shingles, with one edge covered and the other exposed.
This particular species is hermaphroditic, possessing both male and female reproductive organs, with pollination primarily facilitated by insects.
II. How to Grow and Care
Sunlight
Although you can find some Rubus species under the forest canopy, Pennsylvania blackberry loves sunlight. Full sun or partial shade (6-8 hours of sunshine) will be the best for it to thrive. Avoid too crowded bush to allow ample sunlight and air movement, which will prevent your plant from diseases.
Temperature
As a large genus, Rubus has a wide distribution range which means you are always likely to find a proper species or cultivar that grows well in your garden. Generally, Rubus species flourish in temperate zones, and are adaptable to slightly harsh conditions. Select cultivars that may thrive in your garden, thus the preferable climate will encourage them to bear more edible fruits. Pennsylvania blackberry prefers moist to slightly dry conditions, so it is important to avoid waterlogging.
Watering
Your Pennsylvania blackberry needs little care once established, so making sure it receives about 2.5 cm water per week is the only advice on watering. If your plant is grown in containers, you can water more according to the soil condition. Water deep when the topsoil is dry and slightly whitish. Never forget to keep the soil well-drained.
Soil
Pennsylvania blackberry is not picky about soil, as long as the soil is slightly acidic and well-drained. The ideal soil pH range for it is 5.5–7 while a few species and cultivars of Rubus may tolerate slightly alkaline soil as well. Rich loamy soil mixing with some sandy soil can be a good option. Always remember to avoid the heavy clay soil because it can become soggy easily. Hilled soils that promote drainage can also be taken into consideration, instead of wet, flat fields.
Fertilizing
At the pre-planting stage, you can prepare the soil by fertilizing with a balanced fertilizer (N-P-K: 10-10-10). After planting your pennsylvania blackberry, the best care you can give to it is to spread a mulch at the base of the row each year, which works similarly with slow-release fertilizer. You can do this every early spring or late fall. During growing season and fruiting season, you can also apply some balanced fertilizers for fruiting plants once every two to three months. Fertilizing your pot plants more or less the same as with your garden ones.
Planting Instructions
Generally, Pennsylvania blackberry is planted with saplings that are easily purchased from nursery or gardening stores. Avoid Pennsylvania blackberry collected in the forest as diseases are a big problem for wild Rubus.
plant your pennsylvania blackberry in winter or early spring in your garden. Pennsylvania blackberry grows wild where there is much sunlight from above and a wealth of leaf litter, otherwise known as mulch or organic matter in the soil below. Because of this, your planting site is recommended to have ample sunlight and you should have organic matter such as grass clippings readily available. Keep your plants far away from any wild brambles to keep them healthy. Also, plant your Pennsylvania blackberry in separate rows. The optimum spacing can be achieved by creating rows about 3 m apart with plants 60 cm apart within each row. Set a trellis on each side and tie the canes onto the trellis line or wire.
Pennsylvania blackberry will spread both rapidly and at long distances. If you do not want it everywhere in your garden, regularly prune it or grow it in containers. You are recommended to find a prickle-free and small variety to plant in pot, which may be handy for you. Use a shallow but large container for it because its roots spread shallowly outward. Potting soil and sunny place are standards for Pennsylvania blackberry.
Pruning
Pruning is important for Pennsylvania blackberry growers. Prune all canes that bore fruit this year down to the bottom right after harvest. All first-year canes should be cut about half to stimulate lateral growth from the side every late winter or early spring. Remove all suckers and trim overcrowded canes. Pennsylvania blackberry grown in patches must be pruned to ensure that individual canes are not touching to avoid disease infections. Be sure to remove any thinned or pruned canes from the field because old canes left on the ground can harbor disease.
Propagation
Both roots and stem cuttings can be planted to propagate new individual plants. Because of this, make sure to purchase plants from a reputable nursery, otherwise diseases are spread everywhere with your new individuals. You can do root cutting in late winter to ensure the threat of hard frosts is gone, or stem cutting in early summer. The operations are the same. Cut a 10 cm long root or stem and plant it into the moist, clean soil. Keep the soil moist and it will take 2-4 weeks to root.
If you try to grow pennsylvania blackberry from seeds, remember that you must recreate a harsh environment such as exists in the birds’ crop (digestive tract) where sand, pebbles, and seeds churn. Therefore, you must scrap the seed with a file or sandpaper to open up the tough seed coat and allow it to sprout. Sow in early fall in the ground and some may need cold treatment at 3 ℃ for a month before sowing at the beginning of the following year. There is no specific care required after sowing and you can transplant larger seedlings where they can grow better.
III. Uses and Benefits
- Culinary uses
These blackberries can be used for inks or for dyeing clothes, which is not a new practice. Blackberries are also a good source of nutrients and are eaten dried by Native Americans. Fruits can be made into jams and jellies.
- Wildlife uses
The leaves serve as a browse for white-tailed deer. This bramble is year-round exceptional cover for wildlife. The fruits are an important resource for songbirds, small mammals, foxes, raccoons, and even black bears. As winter arrives, birds and small mammals eat the seeds left behind from decomposed fruit. The flowers attract butterflies and various other pollinators.
IV. Harvesting and Storage
Taste the fruit and it will tell you when it is time to harvest. Ripe fruits will be sweet and juicy. If they are still sour or tart, let them ripen a bit longer. Usually you can start harvesting from mid-summer till mid-fall, according to varieties. You should harvest the fruits when all dews or raindrops are dry to prevent molds. They have a short shelf life, so refrigerate them after harvest without washing. As for some sour species, process them into delicious jams or jellies.