Ivy League universities get their nickname from the Boston ivy that climbs their storied walls. 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 flowers, yielding to clusters of dark blue berries that feed birds. The vine length of mature plants may reach 50 feet or more. These colorful and versatile plants have several uses in landscaping.
|Botanical Name||Parthenocissus tricuspidata|
|Common Name||Boston ivy|
|Plant Type||Perennial, deciduous, broadleaf vine|
|Mature Size||30 to 50 feet|
|Sun Exposure||Full sun, part shade|
|Soil pH||5 to 7.5|
|Bloom Time||June to July|
|Flower Color||Greenish white|
|Hardiness Zones||4, 5, 6, 7, 8|
|Native Area||China and Japan|
How to Grow Boston Ivy
Boston ivy is a true climber, attaching to masonry and wooden surfaces using holdfasts (aerial roots). Alternatively, you can let it spread out horizontally to function as ground covers. If you don't want the ivy to grow up walls, plant it 15 feet from any structure. Growing Boston ivy plants up garden arbors, pergolas, and fences are all sound practices. You can grow them on a trellis, as well, especially if you need a privacy screen in summer for a specific area of the yard.
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 1.5 to 2 feet between plants or 1 foot between root cuttings when planting for wall coverage.
If you wish to allow Boston ivy to scale the walls of any buildings, make sure first that you desire it as a permanent fixture. Once the vine gets a toehold, it is difficult to remove it from walls, so tightly do the holdfasts at the end of its tendrils hold it on the supporting structure. You could do damage to a wall in your attempts to rid it of entrenched Boston ivy. It is 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 wall.
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.
Grow the vines in partial shade to full sun. While it will tolerate full shade, planting Boston ivy plants in full sun allows them to achieve maximal fall color. In areas that have hotter summers, Boston ivy plants might do best on walls facing east or north.
Boston ivy does best in well-drained, loamy soil, but it will tolerate many different soil conditions, as well as urban pollution.
Their water needs are average. During the first growing season, ensure it is deeply watered so the roots develop well. After that, water the ivy approximately weekly, and more often when it is hot. It is fairly drought tolerant once it is established.
Temperature and Humidity
Boston ivy will do fine as long as the usual winter temperature doesn't drop below -10 degrees Fahrenheit. New growth might be damaged by late frosts.
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 would be fine for any fertilizing that you feel you need to do after that.
Propagating Boston Ivy
To propagate Boston ivy, take cuttings in the spring from healthy-looking stems. Include about five to six nodes in the cutting. Remove all but two to three pairs of leaves. Apply rooting hormone and plant the cutting in cactus mix or a blend of Perlite and peat moss. Water from the bottom and transplant to a soil mixture once the roots have developed.
Varieties of Boston Ivy
When you shop for Boston ivy at a garden center, you will often find it being sold as a cultivar. Cultivars include:
- "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 and 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 odd cultivar in that its spring foliage color is yellow. The leaves change to green in summer, then to red in autumn.
Toxicity of Boston Ivy
The berries of this vine contain oxalates and are poisonous if eaten, whether by people or pets, although wild birds do eat the berries. Be sure to educate children not to eat these berries. The crystals will irritate the lips and tongue. Seek medical attention promptly. Some people also experience an allergic reaction to Boston ivy upon contact.
These plants are vigorous growers. Prune the vines once each year (in late winter), so as 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 vines that have grown beyond the territory that you want them to cover). The vines respond well to pruning, so have no fear.
Boston Ivy vs. Virginia Creeper vs. English Ivy
Boston ivy is related to another vine, Virginia creeper (Parthenocissus quinquefolia). For identification purposes, note that Virginia creeper's leaf is a compound leaf, composed of five leaflets. Boston ivy's leaf may be compound on young plants but, in such cases, it will display three leaflets. Once mature, Boston ivy bears a simple, not a compound leaf. The vine is also sometimes confused with English ivy (Hedera helix) by beginning gardeners, but the two plants are not related; moreover, English ivy is evergreen, while Boston ivy is not. Plants in the genus, Hedera are true ivies. Others may have common names that contain that word (Boston ivy and the dreaded poison ivy being examples), but they are not real ivies.
Guide to Poisonous Plants. Colorado State University College of Veterinary Medicine