From our perspective as plants, sweet peas are ambitious climbers, sending out delicate tendrils in search of a structure to conquer. We greatly appreciate companions who provide a sturdy framework without competing for that vertical real estate. Tall, strong-stemmed plants like corn (Zea mays) or sunflowers (Helianthus annuus) are ideal. They offer us a natural trellis to scramble up, saving the gardener from installing extra supports. Furthermore, their height provides dappled shade for our root systems, which prefer to stay cool and moist. This symbiotic relationship allows us to focus our energy on producing more of the fragrant blooms we are known for, while our supporters gain the benefit of our vibrant colors weaving through their stalks.
We sweet peas, along with our cousins like beans and clover, have a special ability. We form a symbiotic relationship with Rhizobia bacteria in the soil, which allows us to "fix" atmospheric nitrogen into a form other plants can use. While we use much of this nitrogen for our own growth, we can still be beneficial to heavy feeders planted nearby. However, the most efficient companions in this regard are other low-growing legumes, such as bush beans or clover. They help enrich the soil without becoming overly competitive, creating a mutually beneficial nitrogen-rich environment that reduces the need for external fertilizers and supports a healthier plant community overall.
Our most valued companions are those who engage in what gardeners call "associative resistance." Strong-scented herbs are excellent at this. When you plant aromatic species like lavender (Lavandula), rosemary (Salvia rosmarinus), or sage (Salvia officinalis) near us, their powerful essential oils mask our sweet scent. This confuses pests like aphids, which might otherwise be drawn to our succulent new growth. Similarly, the pungent aroma of onions, garlic, and chives acts as a natural repellent, creating a protective barrier around us. These companions help us stay healthier, reducing the need for any interventions and allowing us to thrive in a more natural, balanced ecosystem.
Our roots are shallow and appreciate a cool, consistently moist environment. Bare, sun-baked soil is stressful for us. This is where low-growing ground cover plants become perfect partners. Species like nasturtiums (Tropaeolum majus) or sweet alyssum (Lobularia maritima) spread out to form a living mulch. They shade the soil, conserving precious moisture and suppressing weeds that would otherwise compete with us for water and nutrients. Nasturtiums offer an additional benefit; they are known as a "trap crop," attracting aphids away from our stems and leaves. This sacrificial nature protects us and allows us to direct more energy into flowering.
