Companion planting is a philosophy of planting crops together based on their needs and habits. Some benefits include improved flavor, increased yield, better pest resistance, and environmental benefits (like shelter from strong winds or sun).
However, not all plants work well together.
These 13 plants are less than ideal companions you should avoid planting near your blackberries. They are all wonderful plants in their own right but should be grown separately from your berry patch.
There are many “good” companion plants for blackberries, including some that can be grown in containers!
If you are thinking about planting blackberry vines this year or are looking for ways to maximize garden space, it is important to know what companion plants you should avoid planting in your blackberry patch. These crops could potentially reduce your berry yields!
Artichokes
These massive plants outcompete berries due to their high nutrient needs, reducing fruit yield.
Artichokes are gorgeous plants that produce wonderful, elegant vegetables. They are also aggressive nutrient consumers, making them a bad companion for berries. Artichokes need a considerable amount of fertilizer to be productive. Blackberries, on the other hand, are relatively light feeders.
Blackberries will use excess fertilizer to promote wood and leaf growth, which leads to decreased fruit production.
Artichoke plants also grow quite large and can easily crowd your blackberry plants, leaving them partially in the shade where fewer berries will grow. Artichokes are just too aggressive in their needs and growing habits, and you should avoid planting them as a blackberry companion.
Asparagus
Blackberries and asparagus compete for nutrients and space, harming yields and weakening plants.
Asparagus is another heavy feeder that makes a bad companion with blackberries. These berry vines prefer light, infrequent fertilizing. On the other hand, asparagus needs a lot of nitrogen. Meeting the needs of asparagus plants will encourage stem and leaf growth in blackberries, leading to a reduced yield.
In addition to different nutrient needs, both plants are vigorous multipliers. Aggressive asparagus plants and blackberry vines will compete for space in the garden. This is true for their roots as well as their foliage.
Perhaps most detrimental in this pairing is the competition of root space between these plants. A weak root system makes for a weak plant with a reduced nutrient intake, and both varieties have extensive, spreading roots.
Canna Lillies
These gorgeous flowers crowd blackberry plants, depriving them of nutrients and making them unsuitable garden companions.
Canna lilies are stunning, stately plants that bloom around the same time as blackberries. Planting these pretty flowering plants near your berry garden might be tempting, but they are typically considered bad companions for fruit and vegetable crops.
Canna multiplies underground via a network of rhizomes. This is why they tend to have a clumping habit and will spread in size, creating a large mass of foliage above the ground and a large mass of rhizomes underground.
In short, canna lilies will crowd blackberry vines and deprive them of nutrients, so these two don’t make good companions in the garden.
Carrots
Due to their differing fertilizer needs, these roots are not suitable companions for blackberries.
You would think that these two plants could grow together harmoniously, with carrots taking up very little space and the ability to be planted here or there very easily. Unfortunately, carrots are a companion you should avoid planting near your blackberry patch.
The main reason they don’t mesh is that carrots need more fertilizer than blackberries do. In addition, the spreading roots of blackberry vines can quickly swallow carrot seedlings, making it difficult to yield these tasty roots. Reserve your carrots for raised vegetable beds with loose soil and no competition for root space.
Cowpea
Although productive and nitrogen-fixing, cowpeas can overcrowd and outcompete your berries.
The cowpea is a great plant that is a big producer of what is more commonly referred to as black-eyed peas. On the New Year’s Day table, these tasty legumes represent luck, and the vines are nitrogen fixers, so they don’t compete for nutrients like some others on this list tend to do.
The problem with cowpea is that it is a vigorous spreader. It always promises to be a bumper crop and is almost too easy to grow. What’s difficult is holding it back.
The incompatibility here revolves around cowpea’s ability to drown out blackberry plants entirely. In fact, it’s a great crop to plant if you’re looking to eliminate wild blackberries.
Eggplant
As heavy feeders, eggplants are a blackberry companion to avoid because they need extra fertilization, decreasing blackberry yields.
Eggplant is a nightshade vegetable with many possible companions. As collaborative as it can be, eggplant doesn’t mesh well with blackberries. Nightshades are notoriously heavy feeders, so any companion you give them needs to be able to go toe to toe in this regard.
Trying to make blackberries match up with eggplants will result in one of two things:
- A lack of fertilizing of the eggplants will lead them to suck up all the surrounding nutrients, leaving your berries foundering for nutrients.
- Conversely, in trying to keep up with feeding your eggplants what they need, blackberry vines will be overfed, leading to decreased fruit.
Fennel
As an allelopathic plant, fennel may inhibit the growth of neighboring plants, reducing their yield.
Fennel makes a great potted plant and is both fragrant and delicious in the kitchen. In the vegetable garden, however, it makes for a toxic neighbor. Research shows that fennel is somewhat allelopathic to most other plants. This means that its roots emit a chemical that may act as a growth inhibitor to the plants around it.
This pairing will leave blackberry plants struggling to obtain new growth, resulting in a greatly reduced yield the following year. Fennel is best kept as a potted plant in its own space.
This way, you can move them close to outdoor living areas where their feathery plumes of foliage and spicy scent can be enjoyed without harming your other plants.
Grapes
Grapevines outpace and overshadow blackberries, crowding them above and below the ground and limiting sunlight.
Simply put, grapevines will crowd blackberry vines into extinction. Both plants have similar growth habits and needs. However, grapes are more vigorous growers, and unless they are kept in check, they will quickly crowd your berries both above and below the ground.
Grape foliage is much larger and more lush than that of blackberry plants. Grapes will outpace blackberries rapidly throughout a growing season, depriving your berries of much-needed sunlight.
Oregano
Although beneficial in the garden, oregano can choke out blackberries and prefers different soil conditions.
Oregano has many benefits in the garden. It is often considered pest-repellent, making it a valuable companion plant. But it’s not the best companion for blackberries.
A single oregano plant isn’t likely to do much damage, but oregano has been known to choke out other plants in its spreading habit. It is sometimes used to eradicate wild blackberries where they are not wanted. It also prefers slightly alkaline soil, the opposite of a blackberry plant.
Peppers
As heavy feeders, peppers require more fertility than blackberries, making them another blackberry companion to avoid.
Peppers are nightshades, so they are heavy feeders. On all other accounts, these shouldn’t cause many issues for blackberries. However, if you want a healthy crop of peppers, you will have to overfeed your blackberry plants, which is more of an issue than it might sound.
These two plants don’t have similar enough environmental needs to be anything special as companions. Peppers do make decent companions in most gardens, but this is a pairing to avoid.
Potatoes
Blackberries and potatoes compete for space and nutrients, resulting in reduced yield and root interference.
Another nightshade, potatoes aren’t good companions for blackberries. Aside from their greater nutritional needs, which will lead to an overgrowth of foliage and reduced yield of berries, they also have a large footprint in the garden.
Potatoes and blackberries will compete for real estate in the root department. Potatoes need room to spread out and form under the ground. Blackberries like to send out roots in all directions, and the two will not only interfere with each other’s growth, but harvesting potatoes will tear up your blackberry roots.
Raspberries
Blackberries and raspberries, while technically compatible, attract more pests and diseases when grown together.
Blackberries and raspberries technically should make good neighbors. In terms of growth habits and environmental needs, they are indeed compatible, and the worst thing that could happen is that they might compete for space. These would work fine together if you’re growing them indoors.
The issue between these two is that they share the same pests, such as the raspberry beetle. They will attract more pests together than they would if paired with something less desirable to those insects. They also share the same diseases, so if one crop is affected, it can quickly spread to the other. Best to maintain some distance between these two.
Tomatoes
Despite being popular and nutrient-rich, tomatoes are incompatible with blackberries due to differing fertilizer needs.
The last on our list is another nightshade vegetable. Tomatoes are one of the most popular vegetables for home gardeners to grow. They are delicious, high in important nutrients, and very easy to grow. Sadly, they make poor companions for blackberries for the same reason that other nightshades fail, nutrient compatibility.
Tomatoes need a lot of fertilizer to live up to their potential. As we have discussed, blackberries do not. Striking the right balance between these two to share the same space is not worth the effort and trouble. Tomatoes are another blackberry companion to avoid.
Final Thoughts
While these plants listed don’t make great companions for blackberries, there are still plenty of ways to utilize companion planting correctly. Find plants with similar needs that won’t compete for space or sunlight. Try planting with blueberries or strawberries for a healthier crop of all berries.
