What to Plant With Parsley: Parsley Companion Plants (and What to Keep Away)

Parsley is one of the easiest herbs to keep in a vegetable garden: a few plants give you leaves from early summer until hard frost, and the curly kinds make a neat edging for a bed. Its companion list is short, but it is clear about both friends and plants to keep away. This guide covers what extension sources list, why the carrot connection matters, how to get the slow seeds to sprout, and how to harvest so the plants keep producing.

Good companion plants for parsley

Tomatoes

Parsley is on Virginia Extension's tomato companion list, and the tomato row lists parsley back. A row of curly parsley, which UMN Extension says grows about 8 to 14 inches tall, fits along the sunny front edge of a tomato bed without competing for light. Plant it a little out from the cages so you can reach it at harvest. More in what to plant with tomatoes.

Asparagus

Asparagus and parsley are listed as companions in both directions. Because an asparagus bed is permanent, small herbs that need no deep digging are a good fit along its edge. See what to plant with asparagus.

Practical extras

Two more pairings come from extension growing advice rather than companion tables. Illinois Extension suggests sowing a few radish seeds in the parsley row: radishes come up in days and mark the row while the parsley is still germinating, so you do not hoe it out by accident. University of Maryland Extension shows curly parsley interplanted with eggplant in a community garden to make the most of the space. Neither is in our checker as a listed pair. See what to plant with radishes and what to plant with eggplant.

What not to plant with parsley

Virginia Extension does not give a reason for each pair, but there are practical ones. Carrots and parsley are close relatives in the carrot family (UMN Extension), and the black swallowtail caterpillars described below feed on both, so a mixed planting gives them one big patch to work through. Mint spreads quickly by underground runners and is easiest to keep in its own pot or bed. For lettuce, simply give each its own row. Our carrot and lettuce guides list better neighbors, and every pair to separate is in the keep-apart chart.

Black swallowtail caterpillars on parsley

If you find striped green, black and yellow caterpillars on your parsley, they are probably black swallowtail larvae. UW–Madison Extension notes parsley is a common backyard host, along with dill, fennel, celery and carrot (see what to plant with fennel), and that they are usually not numerous enough to be a real problem. Young caterpillars are dark with a white saddle that mimics a bird dropping.

• Share: Mississippi State Extension's advice is simply to plant enough parsley and dill for both you and the caterpillars, which become swallowtail butterflies.
• Move them: if they are eating too much, UW–Madison suggests handpicking them and, if you like, moving them to a host plant outside the vegetable garden.
• Skip the spray: UW–Madison says insecticides are rarely justified for them. Our dill guide covers the same caterpillars on dill.

Curly, flat-leaf or root parsley?

UMN Extension describes curly parsley as compact (about 8 to 14 inches), good for borders, interplanting and containers. Italian flat-leaf parsley grows two to three feet tall with a looser habit and a stronger flavor that many cooks prefer. Hamburg parsley is grown for its white, parsnip-like root. All three grow the same way.

When to plant parsley

UMN Extension says direct seeding is the easiest way to grow parsley: sow outdoors after the danger of spring frost has passed. You can also start seeds indoors six to eight weeks before your last frost. Illinois Extension cautions that parsley has a taproot, so handle transplants carefully and avoid damaging it. Our planting calendar shows your frost date. (Its faster-growing cousin cilantro is covered in what to plant with cilantro.)

Sowing, germination and spacing

• Slow to sprout: UMN gives two to five weeks for germination, depending on how fresh the seed is. Soaking seeds in warm water for up to 24 hours speeds it up.
• Depth: cover seeds with about ⅛ inch of soil and keep them moist. Mark the row, since the seedlings look grass-like at first.
• Spacing: thin or transplant seedlings at 2 to 3 inches tall, to a final 10 to 12 inches apart.
• Sun: six to eight hours of direct sun is best; parsley tolerates some light shade (UMN), and Illinois notes it grows in partial shade.

Watering and feeding

UMN Extension recommends not letting parsley dry out completely: water deeply at least once a week, and use a light mulch of shredded leaves or grass clippings to hold moisture and keep weeds down. It grows best in well-drained soil rich in organic matter, with a pH of about 6.0 to 7.0. Have your soil tested and follow the report before adding fertilizer.

Harvest

UMN Extension advises snipping whole stalks close to the ground, starting with the outside stalks, so new growth keeps coming from the center; cutting just the tops leaves stubs and makes the plant less productive. Parsley handles light frosts and stays productive into fall. It is a biennial: if it survives the winter it sends up a seed stalk the next year, and Illinois Extension notes the second-year leaves are tough and bitter, so most gardeners sow new plants each spring. Fresh parsley has the best flavor; UMN notes drying or freezing loses much of it.

Two simple ways to use parsley

1. Tomato bed edge.

   Curly parsley along the sunny front edge, with basil between the tomato cages. Carrots and lettuce go in a different bed.

2. Asparagus row edge.

   Parsley and basil along the south side of a permanent asparagus row, where no deep digging is needed.

3. Butterfly patch.

   A few extra parsley and dill plants at the edge of the garden for swallowtail caterpillars, away from your carrots.

Frequently asked questions

What grows well with parsley?

Virginia Extension lists tomatoes and asparagus as companion plants for parsley, and both crops list parsley back.

What should you not plant with parsley?

Virginia Extension lists carrots, lettuce and mint as incompatible with parsley. Carrots are close relatives in the same plant family, and mint spreads aggressively, so give each its own space.

Why is my parsley taking so long to come up?

Parsley is slow: University of Minnesota Extension gives two to five weeks for germination. Soaking seeds in warm water for up to 24 hours speeds it up, and keeping the soil moist helps.

What is eating my parsley?

Striped green, black and yellow caterpillars are usually black swallowtail larvae. They rarely do serious damage; you can plant extra parsley to share or move them to another host plant.

Does parsley come back every year?

Parsley is a biennial. If it survives the winter it flowers and sets seed the next year, and the second-year leaves are tougher and more bitter, so most gardeners sow new plants each spring.