Rhubarb Companion Plants: The Best and Worst Pairings

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rhubarb companion plants
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With its vibrant red stalks and striking, oversized leaves, rhubarb would effortlessly steal the show in any garden. Bring in a few trusty rhubarb companion plants with it, and be ready for an awe-inspiring display to take center stage in your garden.

Rhubarb is a hardy perennial that can tolerate frost and temperatures as low as 25 degrees. It’s among the first plants to emerge in the spring and can be harvested multiple times throughout the growing season. However, to guarantee a successful rhubarb harvest, you must be selective about which plants you grow alongside it.

Whether you’re a seasoned gardener or just starting out, this rhubarb companion planting guide will give you the lowdown on the best and worst plants to grow with rhubarb.

Let’s dive in!

A close-up vertical image of bright red rhubarb stalks

What is Companion Planting?

Just like some plants compete for sunlight, nutrients, and space in the garden, others share a mutually beneficial relationship. Companion planting capitalizes on this relationship by grouping plants together that benefit each other in some way. It has been practiced for centuries by gardeners worldwide and is an environmentally friendly way to control pests, improve soil health, and boost crop yields.

The Benefits of Companion Planting for Rhubarb

Planting rhubarb with suitable companions can have several benefits, including:

  • Improved soil quality: Beans and peas fix nitrogen in the soil, making the nutrient more available for uptake by rhubarb.
  • Natural pest control: Rhubarb contains oxalic acid in its leaves, making them unappealing to many pests. However, fungal diseases like rhubarb crown rot can still be an issue. Planting garlic, chives, or onions nearby reduces the risk of fungus and also deters other pests.
  • Space saving: Strategically planting smaller plants such as herbs and chard around rhubarb can fill the spaces between rhubarb rows with minimum competition.
  • Natural mulch: Plants like strawberries and spinach serve as organic mulch, regulating soil temperature and moisture content.

Understanding the Needs of Rhubarb: (A Quick Care Guide)

As a perennial, rhubarb begins its growth in early spring, thrives throughout summer, and dies down in the fall to return the following spring. It loves full sun (at least six hours of direct sunlight daily) and prefers well-draining, fertile soil with a pH level between 6.5 and 6.9. Once established, rhubarb can handle occasional dry spells, but consistent moisture is essential for optimal growth and fruitful harvests.

Given its preference for cooler climates, you’ll need to provide some shade during peak summer weather to prevent wilting. Make sure there’s a good 3-4 feet distance between individual plants for air circulation. A little nourishment in the form of compost or aged manure at the beginning of spring will set it up for the season.

And a little tip: hold back from harvesting stalks in the first year of growth, allowing the rhubarb to establish itself for future harvests.

Best Rhubarb Companion Plants

Now let’s take a look at some of the best plants to grow with rhubarb and the benefits they bring to your garden:

1. Snap Beans

Beans are the perfect rhubarb companion as they add nitrogen to the soil and have shallow roots that won’t compete with rhubarb. Plus, they love the same water and soil conditions. And the best part? They have super compatible growing seasons—rhubarb finishes producing in mid-summer, just as snap beans are ready to be harvested. To make sure both plants thrive, give them plenty of space.

Ideally, plant them in alternate rows 2-3 feet apart. This way, they won’t overshadow each other or battle for nutrients.

2. Spinach

Spinach is a fantastic companion for maximizing your garden space. Sown in early fall, winter spinach fills the void left by receding rhubarb, acting as a protective mulch against frost damage. Furthermore, its presence ensures the soil remains aerated and moist, making it easier for the rhubarb plant to establish itself in the next season.

Just remember, spinach is a voracious feeder, so it’s crucial to replenish the soil post-harvest and rotate the planting location annually.

3. Kale

Spring-sown kale reaches maturity in midsummer. At this stage, it needs some shade to keep it from getting bitter. Rhubarb offers the perfect amount of shade to keep the kale happy under the scorching sun. As the season goes on, the rhubarb will gradually fade away, giving the kale all the space and sunlight it needs to keep producing until winter.

Plant the kale to the south of the rhubarb row so it gets shade from the rhubarb during summer, and not the other way around.

4. Swiss Chard

Similar to kale, Swiss chard appreciates occasional shade during torrid summer days. Being a low-maintenance vegetable with fairly compact growth, it also fits snugly between rhubarb rows without causing competition.

To get optimal results, keep harvesting the larger outer leaves of chard, which encourages new growth and gives the rhubarb room to expand.

5. Alliums

While rhubarb naturally repels pests, adding alliums like garlic and onions enhances this protective barrier. Alliums also add sulfur to the soil, which is essential to fight root fungus, one of the major rhubarb problems.

The key with alliums is positioning; they don’t compromise on sun, so you’d want to keep them around 2-3 feet away from your rhubarb, preferably on the north side.

6. Strawberries

Strawberries are a classic companion for rhubarb, and it’s not hard to see why. They love the same soil and water conditions, do not compete for space or nutrients, and complement each other perfectly in recipes. Additionally, strawberries act as a natural mulch, preventing weed growth and retaining moisture for both plants.

But the best part is that rhubarb also acts as a trap crop for your strawberries. Slugs, which are common pests for strawberries, are drawn to the rhubarb leaves (which aren’t edible anyway), leaving your berries alone. To make the most of this dynamic duo, plant strawberries in a ring around the rhubarb crown, giving both plants enough space to thrive.

7. Herbs

Herbs like chamomile, comfrey, and catnip are all great additions to a rhubarb garden. Chamomile provides good water retention and helps prevent soil erosion, while comfrey adds potassium and other nutrients to the soil. Catnip can help repel pests like aphids, which can be harmful to both the rhubarb plant and its companions.

In addition, all three herbs are low-growing and won’t compete with rhubarb for space. Plant them in between rhubarb rows or around the perimeter of your garden bed to reap their benefits.

Worst Rhubarb Companion Plants

While many plants complement rhubarb, some can negatively affect its growth. Here are a few plants you should think twice about planting near your rhubarb:

Melons: Melons have specific water requirements and may not appreciate moisture-loving rhubarb around them, causing rot. They also tend to spread and can dominate a garden bed, potentially smothering the rhubarb.

Peppers and Eggplants: These heat-loving plants don’t mix well with the shade offered by rhubarb. They can also be more susceptible to root rot and fungal diseases, especially if planted too close together.

Potatoes: Potatoes take up a lot of space underground and can disturb the deep roots of rhubarb. As heavy feeders, potatoes can also lead to stunted, short-lived rhubarb plants.

Sunflowers: Sunflowers have allelopathy, meaning they produce chemicals that can inhibit the growth of other plants. Additionally, they grow really fast and can potentially invade and shade out your rhubarb pretty quickly.

Frequently Asked Questions

What should you not plant next to rhubarb?

Avoid planting invasive and competitive plants such as potatoes and sunflowers near your rhubarb. Additionally, steer clear of plants with significantly different water needs, like melons and peppers.

What grows best with rhubarb?

Plants that tolerate partial shade, enjoy moist soil, and have modest space and nutrient needs are ideal companions for rhubarb. Some examples are spinach, kale, beans, Swiss chard, strawberries, and herbs such as chamomile and comfrey.

Is rhubarb poisonous to other plants?

Rhubarb isn’t poisonous to any plants at all. However, its leaves do have high levels of oxalic acid, which makes them unappealing to pests. That’s why they are often used in organic pest repellents. It’s also the reason why we only eat the rhubarb stalks, not the leaves.

Can I plant rhubarb in a container?

Absolutely, you can grow rhubarb in a container, provided it’s spacious enough for the plant’s deep roots and has good drainage. Remember that rhubarb needs rich organic soil, so keep an eye on the nutrient levels and fertilize regularly. And don’t forget to water consistently, as containers can dry out pretty quickly in warm weather.

Final Thoughts

A long-living perennial like rhubarb can benefit significantly from good company. Good rhubarb companion plants such as strawberries and alliums can not only provide added nutrients and protection but also help maximize the use of your garden space. Other plants, like melons and sunflowers, can potentially harm your rhubarb’s growth.

So, next time you plan your garden, remember these friendly and not-so-friendly neighbors for your rhubarb plants.

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