The Right Place
These two bittersweets vary in hardiness. Oriental bittersweet is the less hardy of the two, flourishing only as far north as the Ohio River Valley, into Southeastern Pennsylvania and up the Atlantic seaboard into Rhode Island (zone 5). It can handle winter temperatures that only dip to -10° F. American bittersweet can withstand much colder winters and grows well as far north as, and into, Canada (zone 2).
Bittersweet can handle shade, but produces more fruit if it has plenty of sun. Extremely adaptable, these vines grow in almost any type of soil, even infertile clays and sands. They prefer it to be slightly acid, if possible (pH 6.1 to 7.5). Plants are now available in nurseries in containers. Buy 2 or 3 year old bittersweet plants in the fall when the fruit is visible, to differentiate between male and female plants. Both are required for fruiting. Plant bittersweet plants within several yards of one another to promote pollination. Bittersweet has deep, long roots which makes it difficult to transplant.
Planting Nursery Stock
Plant in the fall. Remove the container from the plant and loosen any roots that have become matted. Trim those that may have begun to grow in a circular pattern at the bottom of the container to prevent them from continuing to grow around themselves. Dig a hole wide enough to accommodate the roots and soil from the container and deep enough to assure that the plant is at the same depth as it was in the container. Set the plant in the hole, check that it is level with the soil surface, and fill in the hole with dirt. Firm the dirt around the vine stem, then water. Do not fertilize at this time. It may take several years, usually about 8 years for American bittersweet, for these vines to begin bearing fruit.
Amendments In Planting or Transplanting
There are a number of products at the garden center that will help your newly planted or transplanted plants deal better with the stress inherent in the planting process. All healthy plants have beneficial fungi, called mycorrhizal fungi, living on their roots. You can buy these valuable additions to your plant’s ecosystem. See the file describing Using Micorrhizae When Planting.
In addition, there are a number of products such as seaweed, compost tea, and beneficial soil microbes that when added to the planting process will help your newly established plants get going faster. See the file New Technology In Plant Growth Activators