Gardening in Australia blends tradition with innovation, particularly in growing asparagus.
When paired with the right companions, asparagus thrives even more.
Companion planting goes beyond space-saving. It fosters a garden ecosystem where other plants support your asparagus as it grows.
Why Companion Planting is Good for Asparagus
Australia’s varied climates mean picking the right friends for your asparagus plants can help them flourish and bring in a great harvest.
For asparagus, this means partnering it with species that can deter pests, enrich the soil, and even improve its flavour.
What Makes a Good Asparagus Companion Plant?
A good asparagus companion plant supports the growth, health, and productivity of asparagus in several ways.
When selecting companion plants for asparagus, consider the following characteristics that make them beneficial partners.
1. Pest deterrence
Choose plants that naturally repel common pests of asparagus, such as the asparagus beetle, aphids, and slugs.
Herbs and flowers with strong scents or specific compounds can act as natural deterrents, reducing the need for chemical pest control.
2. Disease suppression
Some companion plants can help reduce the risk of diseases that affect asparagus. For example, plants that improve air circulation around asparagus spears can help prevent fungal diseases.
Additionally, certain plants might foster beneficial soil organisms that suppress pathogenic fungi or bacteria.
3. Nutrient sharing
Companion plants that fix nitrogen in the soil, such as legumes, can benefit asparagus, which thrives in nutrient-rich soil.
These plants convert atmospheric nitrogen into a form that can be used by neighbouring plants, enhancing soil fertility.
4. Attracting beneficial insects
Plants that attract pollinators or beneficial predatory insects can improve the overall health of the garden.
For instance, flowers like dill and parsley attract beneficial wasps and other predators that control pest populations while also attracting pollinators essential for many fruiting plants.
5. Soil conditioning
Some companions can help improve soil structure or moisture retention, creating a more favourable growing environment for asparagus.
Deep-rooted plants can help break up compacted soil, making it easier for asparagus roots to grow.
6. Mutual support
The best companion plants do not compete aggressively with asparagus for space, light, water, or nutrients.
Instead, they should have complementary growth habits and requirements. For example, low-growing herbs can cover bare soil without overshadowing young asparagus plants.
7. Crop rotation compatibility
Asparagus is a perennial. Its companions should either be beneficial in a long-term setting or easy to rotate without disturbing the asparagus crowns.
Annuals that can be easily replaced or rotated each year without interfering with the asparagus can be good choices.
The Best Asparagus Companion Plants
Here is a list of companion plants for asparagus that love the Aussie climate.
Tomatoes
The classic companion for asparagus, tomato plants help repel asparagus beetles.
The solanine in tomatoes is thought to have a protective effect on asparagus, while asparagus can ward off some of the root nematodes that trouble tomatoes.
Basil
Basil is not just an herb for Italian dishes; it’s a fantastic companion for asparagus, repelling harmful insects and potentially enhancing the vegetable’s flavour.
Its strong scent is believed to deter pests, making it a must-have in your asparagus garden.
Parsley
A friend to many garden plants, parsley attracts beneficial insects like hoverflies, which prey on common pests.
Planting parsley alongside asparagus can contribute to a more balanced ecosystem in your garden.
Marigolds
The bright, cheerful marigold is more than just a pretty face; it’s a powerful deterrent against nematodes and can even discourage some beetles from settling in.
Their ability to protect asparagus roots from underground pests makes them invaluable in Australian gardens.
Nasturtiums
These vibrant flowers are not just for show; they offer a strong line of defence against aphids and beetles.
Planting nasturtiums around the perimeter of your asparagus bed can create a natural barrier, shielding your asparagus from these voracious pests.
What to Avoid Planting Next to Asparagus
Most plants are great, but there are bad companion plants for your asparagus.
By carefully selecting your asparagus companion plants, you can avoid those that could create competition or increase the risk of disease and pest problems.
Cucumbers
Cucumbers can attract cucumber beetles and other pests that might also harm asparagus plants.
Additionally, cucumbers’ sprawling growth habit and heavy water requirements could overshadow and compete with asparagus for resources.
Garlic
While garlic is a powerful pest deterrent for many plants, it can adversely affect asparagus.
Its strong scent and root exudates may inhibit asparagus growth, making it wise to plant garlic away from your asparagus bed.
Melons
Like cucumbers, melons (including watermelons, rockmelons, and others) have similar water and nutrient needs and may compete with asparagus.
They can also attract pests that could harm asparagus plants.
Onions
Onions can inhibit the growth of asparagus by competing for nutrients and possibly introducing pests that target both plants.
It’s best to keep them in separate areas of the garden.
Peppers
Peppers, or capsicum, including sweet and hot varieties, may not be the best neighbours for asparagus.
They share some common pests that could transfer between them, increasing the risk of infestation.
Potatoes
Potatoes and asparagus are not garden friends; they vie for space and nutrients, potentially stunting each other’s growth.
Additionally, potatoes might increase the risk of fungal diseases affecting asparagus plants.
Squash plants
Squash plants, including zucchini, pumpkin, and other varieties, are large, vigorous growers that can overshadow smaller asparagus plants.
Their similar pest attractions and high nutrient demands can negatively affect the health and productivity of asparagus.
Tips for Planting Asparagus
Planting asparagus in your garden is a rewarding endeavour, but it needs a bit of know-how to get things right.
1. Choose the right spot
Asparagus loves the sun, so pick a spot in your garden that gets plenty of it — at least 6 to 8 hours of direct sunlight daily.
Since asparagus is a perennial, you’ll also want to choose a location where it can grow undisturbed for many years.
2. Prepare the soil
Asparagus prefers well-drained, nutrient-rich soil. Work in plenty of organic matter like compost or well-rotted manure before planting to improve soil fertility and structure.
A pH of 6.5 to 7.5 is ideal, so test your soil and adjust accordingly.
3. Plant asparagus crowns
The quickest way to a rich harvest is by planting one-year-old crowns.
Dig trenches about 30 cm wide and 15–20 cm deep, spacing the crowns 30–45 cm apart in rows that are 1–1.5 m apart.
Place the crowns at the bottom of the trench, spread the roots out evenly, and cover with 5–8 cm of soil.
As the plants grow, continue to fill in the trench with soil.
4. Water wisely
Keep the soil consistently moist, especially during the first two growing seasons.
Asparagus roots go deep, so less frequent, but deep watering is better than shallow sprinkles.
5. Mulch for moisture and weed control
Apply a thick layer of organic mulch around your asparagus plants.
This will help retain soil moisture, regulate soil temperature, and suppress weeds that could compete with your asparagus for nutrients.
6. Be patient
The asparagus plant requires and rewards patience.
Avoid harvesting in the first year after planting to allow the plants to establish a strong root system.
In the second year, you can harvest a few spears over a short period.
By the third year, you’ll be rewarded with a more bountiful harvest that can continue for 15 years or more with proper care.
No Need to Be Sassparagus
Caring for an asparagus patch in your vegetable garden is a delicate dance of choosing the right companion plants.
From the protective embrace of tomatoes to the colourful guard of marigolds, each companion plant plays a role in the health and productivity of your asparagus.
Whether you’re a gardening expert or a newcomer, you can transform your garden into a vegetable haven with good companion plants.
