Hollyhocks (Alcea rosea) are classic additions to the cottage garden, instantly recognizable by their towering, vertical flower spikes that can reach heights of over six feet. These statuesque plants create a dramatic backdrop and bring nostalgic charm to any space. Companion planting utilizes specific neighboring plants to support the hollyhock’s health and appearance. This arrangement can improve soil conditions, deter common pests, and provide necessary aesthetic camouflage for the hollyhock’s often bare lower stalks.
Establishing the Right Growing Environment
Successful companion planting requires selecting partners that share the hollyhock’s environmental needs. Hollyhocks demand full sun, meaning a minimum of six hours of direct sunlight daily; insufficient light reduces flowering and weakens the stem structure. Companions must also flourish under these high-light conditions to prevent resource competition.
The soil structure is equally important, requiring a fertile, well-draining medium that prevents waterlogging around the deep taproot. While established hollyhocks are relatively drought-tolerant, they benefit from consistent moisture during their initial growth phase. Good air circulation is also necessary, as it helps quickly dry the foliage and minimizes the chance of fungal diseases like rust.
Low-Growing Companions for Root Health
Low-growing companions planted around the base of a hollyhock stalk serve functional purposes beyond simple aesthetics. These plants, generally under twelve inches tall, act as a living mulch to regulate soil temperature and retain moisture in the root zone. This coverage helps keep the soil consistently cool and damp, benefiting the hollyhock’s root system during hot, dry periods.
Creeping herbs like thyme or sweet alyssum are excellent choices because they form a dense mat that suppresses weed growth. Sweet alyssum also attracts beneficial insects, particularly hoverflies, whose larvae prey on common hollyhock pests like aphids. Aromatic plants such as basil or marigolds can also be incorporated, as their strong scents confuse or repel damaging insects.
Mid-Height Plants for Visual Layering
A common visual challenge is that hollyhock basal leaves often yellow and drop off mid-season, leaving the lower stems bare. Mid-height companions, typically one to three feet tall, are strategically placed in front of the hollyhocks to screen these bare lower stems. This technique creates a visually cohesive border while maintaining the vertical drama of the taller stalks.
Plants with contrasting or complementary forms are selected for this layer:
- Cosmos, with its feathery foliage, softens the hollyhock’s rigid vertical line.
- Foxgloves and delphiniums echo the hollyhock’s verticality, creating a lush, multi-layered look.
- Ornamental grasses, such as fountain grass varieties, offer fine texture and movement that counterpoint the hollyhock’s bolder flowers.
- Perennials like Shasta daisy or coneflower effectively fill the foreground, ensuring vibrant color even after the hollyhock’s lower leaves decline.
Plants to Exclude
To ensure the health of hollyhocks, avoid planting certain species nearby due to the risk of shared disease or aggressive competition. Hollyhocks are highly susceptible to hollyhock rust (Puccinia malvacearum), a fungal disease manifesting as orange pustules on the undersides of the leaves. Therefore, any other plant in the mallow family, such as Lavatera or common mallow, should be excluded, as they can act as a reservoir for fungal spores.
Avoid plants that spread aggressively, like mint, or heavy feeders, as they compete directly with the hollyhock’s deep taproot for water and nutrients. It is also wise to avoid planting near species with opposing cultural needs, such as shade-loving hostas or ferns. Pairing with plants requiring excessive nitrogen fertilization will negatively impact the hollyhock, as high nitrogen promotes heavy leaf growth at the expense of abundant flower spikes.