Apple and Nasturtium

Apple and nasturtium is a well-documented trap-crop pairing. Nasturtiums are planted at or just before bud break, giving them time to establish before aphid populations peak in late spring. The standard approach is to plant them in a ring around the tree's drip line, roughly 2 to 4 feet from the trunk, keeping root competition with shallow apple feeder roots minimal.

Soil compatibility is generally good: nasturtiums tolerate the well-drained, slightly acidic conditions most apple rootstocks prefer, though they struggle in heavy clay and will bolt quickly in nutrient-rich soil, which actually suits the trap-crop role (lush growth attracts pests faster).

The pairing is most useful where black aphid and woolly aphid pressure recurs annually. It is less useful where beneficial insect populations are already strong, since concentrating aphids on a trap plant only helps if that plant is monitored and removed or cut back before colonies migrate to the tree. The benefit for codling moth is more limited and should not substitute for bagging fruit or targeted sprays in high-pressure situations.