Broccoli Companion Plants

Claim. Sweet alyssum strips in organic broccoli supported hoverflies whose larvae eat aphids; field agronomy showed the benefit depends on the share of the bed given to alyssum and its distance from the crop.

Mechanism. Alyssum flowers supply nectar and pollen to adult hoverflies (syrphids), which lay eggs near aphid colonies; larvae consume aphids.

Studied in. Organic broccoli fields, Salinas Valley, California; alyssum in strips or interplanted at 1–10% of the bed. (field)

Conditions. Transplant alyssum at the same time as broccoli so it flowers before aphids build up. Alyssum within a few metres of the broccoli; a few plants per bed are enough. Alyssum must be flowering while aphids are colonising the broccoli.

Management. Keep alyssum to a small share of the bed (about 5% or less); Shear alyssum to rebloom.

Applies when. Hoverflies must be present in the area; in a small garden, the benefit is plausible but not guaranteed.

Limitations. Alyssum is a brassica and can host flea beetles. More alyssum means more competition, not more benefit.

Evidence. Tier B: One or more relevant controlled field studies or an authoritative synthesis tied to the crop, effect and arrangement. (field trial).

Sources. Brennan 2016; Hogg 2011

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record sweet-alyssum--broccoli--insectary_support v1. Request a correction.

Claim. The cabbage–clover pest-disruption effect is expected to transfer to broccoli (the same species, Brassica oleracea) when the ground is fully covered, but the trials were on head cabbage.

Mechanism. Disruption of pest host-finding by non-host ground cover.

Studied in. Cabbage trials; broccoli is a related crop of the same species. (field)

Conditions. Sow clover after broccoli is established. Continuous ground cover. Both plants must be present at the same time.

Management. Mow clover to limit competition.

Applies when. Same conditions as for cabbage.

Limitations. Not directly tested on broccoli; competition reduces head size as in cabbage.

Evidence. Tier B: One or more relevant controlled field studies or an authoritative synthesis tied to the crop, effect and arrangement. (field trial).

Sources. Finch 2000; Theunissen 1995; Carrillo-Reche 2023

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record white-clover--broccoli--living_mulch v1. Request a correction.

Claim. We did not find a source that establishes a benefit or harm between broccoli and tomato.

Mechanism. None documented.

Conditions. Planted together Both plants must be present at the same time.

Applies when. The planner evaluates spacing, light, water and timing normally.

Limitations. See the Brussels sprout record for the only field test of the brassica–tomato tradition; broccoli itself is untested.

Evidence. Unknown: No source meeting the inclusion rules. (none).

Sources. University of Minnesota Extension 2023

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record broccoli--tomato--other v1. Request a correction.