Parsley is a highly popular culinary herb, typically grown as an annual, though it is technically a biennial plant. Cultivating parsley successfully involves understanding its neighbors in the garden, a practice known as companion planting. This technique involves strategically placing different plant species near each other to create a mutually beneficial environment. Companion planting can improve the health and yield of parsley by managing pests and optimizing soil conditions.
Specific Plants That Aid Parsley Growth
Parsley thrives when planted near companions that offer shade, deter pests, or contribute to soil fertility. Asparagus is an excellent companion, as parsley helps repel the asparagus beetle, a common pest of the vegetable. This pairing also maximizes garden space, allowing parsley to fill in the rows while the perennial asparagus spears are not actively producing foliage.
Tomatoes and peppers benefit from parsley’s presence, and their taller stature provides a light, dappled shade that parsley appreciates, especially in the heat of the summer afternoon. Parsley attracts beneficial insects that prey on aphids and repel pests like the tomato hornworm, protecting the vulnerable fruiting plants. Planting the herb at the base of the tomato plant can also help shade the soil, reducing moisture loss.
Legumes such as bush beans and peas are beneficial because they have the unique ability to fix nitrogen from the air into the soil through a symbiotic relationship with bacteria. This process enriches the soil with a nutrient that promotes the lush, green leaf growth desired in parsley. Additionally, parsley’s aromatic foliage is believed to help mask the scent of the legumes, deterring common bean pests.
Growing parsley near roses is a traditional practice said to deter common rose pests, including various flies, wasps, and beetles. The herb’s presence is also reputed to make the scent of the rose blossoms sweeter. Carrots and parsley are members of the same plant family; they can be planted together effectively because their differing root depths prevent competition for nutrients.
How Parsley Benefits the Garden Ecosystem
Parsley’s most significant contribution comes from its ability to attract and support beneficial insect populations. When allowed to flower in its second year, the plant produces umbrella-shaped clusters of tiny blossoms that are irresistible to predatory insects. These flowers provide easy access to nectar for small insects, including parasitic wasps and hoverflies.
The parasitic wasp, such as the braconid wasp, is valued for laying its eggs inside pest larvae, including cabbage worms, codling moths, and armyworms. Hoverflies are also attracted to the flowers; their larvae are voracious predators of aphids and thrips. By encouraging these insects, parsley acts as a natural pest control agent for the garden.
Beyond pest management, parsley serves as a host plant for the black swallowtail butterfly caterpillar. Although the caterpillars consume the leaves, planting extra parsley ensures a supply for these pollinators. Parsley also develops a deep taproot, capable of reaching nutrients and moisture deep within the soil.
When the biennial plant completes its life cycle and dies back, the decomposition of its taproot releases deep-mined nutrients into the topsoil. This process makes the nutrients available to shallower-rooted plants, improving the fertility and structure of the surrounding garden bed.
Plants to Never Grow Near Parsley
Certain plants should be kept away from parsley to prevent issues ranging from aggressive competition to growth inhibition. Members of the mint family, including peppermint and spearmint, are poor companions due to their invasive, rapidly spreading root systems. Mint quickly outcompetes the more delicate parsley for water and nutrients, making it difficult for the herb to thrive.
Fennel is a notable plant to avoid because it exhibits allelopathy, releasing chemical compounds that stunt the growth of most plants, including parsley. The chemical inhibition from fennel can severely limit parsley’s size and vigor. Similarly, allium species like garlic and onions can impede parsley’s growth when planted in close proximity, leading to smaller harvests.
Dill and cilantro, which belong to the same Apiaceae family as parsley, should be kept separate, especially if a gardener intends to save seeds. If these plants flower at the same time, they can cross-pollinate, leading to hybrid seeds and an undesirable change in the flavor profile. Planting lettuce near parsley is discouraged because parsley can cause the lettuce to bolt prematurely, resulting in a bitter taste.