This deciduous perennial woody vine is remarkably easy to grow, but you will probably need to periodically prune it to keep it in check. Though not as problematic as English ivy, Boston ivy can damage wood siding, gutters, and even roofing if it is left unsupervised. In scattered parts of North America, this native of China and Japan is regarded as an invasive plant, and growing it is discouraged. But where suitable, Boston ivy is always a better choice than English ivy. Boston ivy vines not only lend greenery through the summer, but they also provide fall color. In spring, the new leaves of Boston ivy are reddish. The leaves typically turn green in summer before reverting to a reddish color in fall. The plants produce inconspicuous greenish-white flowers in June to July, yielding to clusters of dark blue berries that birds enjoy. Boston ivy is generally planted from potted nursery starts in late spring or early summer. It is a fast-growing vine that can add 3 to 10 feet each year. Mature plants can reach 50 feet and sometimes even more. The oxalates in the berries of Boston ivy, which are toxic to humans can also be toxic to pets. The vines are also grown up walls for that Ivy League look, as well as to shade the wall for energy efficiency. Give the roots enough room by planting them 1 foot from the wall, and allow 18 to 24 inches between plants when planting for wall coverage. If you wish to allow Boston ivy to scale building walls, make sure you’re truly at peace with the idea of it becoming a permanent fixture. Once this vine gets a toehold, it’s difficult to remove it from walls—you can damage a wall attempting to tear off an entrenched Boston ivy. It’s better to train the vine to grow on trellises and similar structures unless you are sure that you want it as permanent “siding” on your walls. Don’t allow Boston ivy to climb a tree. The shade cast by the vine will interfere with a tree’s photosynthesis, thereby depriving it of nutrients.
Light
Grow these vines in partial shade to full sun. While it will tolerate full shade, Boston ivy needs full sun to achieve maximal fall color. In areas that have hotter summers, Boston ivy plants do best on walls facing east or north, where they get some shelter from the sun.
Soil
Boston ivy does best in well-drained, loamy soil of a pH between 5.0 and 7.5 but it will tolerate many different soil conditions, as well as urban pollution.
Water
Boston ivy has average water needs. During the first growing season, ensure it is deeply watered so the roots develop well. After that, water the ivy weekly, and more often when it is hot. The plant is fairly drought tolerant once it is well established.
Temperature and Humidity
Boston ivy generally does well in the temperatures common to its hardiness zone range—zones 4 to 8. Plants in exposed locations can sometimes be permanently damaged if winter temperatures fall below minus 10 degrees Fahrenheit. New growth can sometimes be damaged by late spring frosts, but the plant usually recovers quickly.
Fertilizer
While fertilizing is often unnecessary, some growers apply a fertilizer high in phosphorus (the middle number in the NPK sequence) at planting time to encourage root development. An all-purpose fertilizer is fine for feeding in the spring. For the amount to use, follow the product label instructions.
Boston Ivy Varieties
When you shop for Boston ivy at a garden center, you will often find named cultivars rather than the species plant. Consider these popular cultivars:
‘Purpurea’ and ‘Atropurpurea’ are similar, but the foliage of the former stays a more constant reddish-purple from spring to fall.‘Veitchii’ starts out purple, is green in summer, then turns crimson in fall. It is marked by its smaller leaf size. By contrast, ‘Green Showers’ has leaves larger than those of most Boston ivy cultivars.‘Fenway Park’ is an unusual cultivar with spring foliage that is yellow. The leaves change to green in summer, then to red in autumn.
Pruning
These plants are vigorous growers. Prune the vines once each year (in late winter when dormant), to check the rapid growth. Simply prune away any growth that is out of place (either vines that are sticking out in an unsightly way or those that have grown beyond acceptable territory). The vines respond well to pruning, so have no fear of damaging them. Prune only one-third of the plant at a time. If you need to remove the vine from walls, do not rip it off–it can damage the wall. Removing Boston ivy from walls can also leave behind the suckers, which are difficult to remove. Instead, cut the vine at the base of the plant, allowing the vine to die. Once the vine has died back, it’s easier to to remove from the wall without leaving suckers behind.
Propagating Boston Ivy
Boston ivy is propagated in the spring:
How to Grow Boston Ivy From Seed
Boston ivy can also be propagated from seeds collected from the berries. Harvest some berries when they are ripe and full, then crush them and carefully remove the seeds from the pulp. Wash and dry the seeds on paper towels. Store the seeds in a bag or container filled with some loose sand in the refrigerator for about two months, which will simulate the natural plant cycle. In early spring, plant the seeds in the desired location, about 1/2 inch deep, and keep well-watered until the plants sprout and become well established. You can also sow the seeds in small pots, then transplant them into the garden once they are several inches tall. Note that seeds from hybrid plants may not grow true to the parent.
Common Pests & Diseases
As you might expect from a plant with a reputation for aggressive, sometimes invasive, growth, Boston ivy is not often affected by serious problems. But they are sometimes plagued with scale, which can cause plants to turn yellow, then lose their leaves in spring or summer. If this occurs, carefully inspect the vine stems for the small scabby lumps that indicate scale insects. Large infestations can be treated with a spray mixture of one tablespoon of alcohol mixed with a pint of insecticidal soap. Another common problem is powdery mildew, which creates a powdery white residue on the leaves. This rarely kills the plant, but if necessary it can be treated with a sulfur spray in two applications, spaced two weeks apart.
