Garden balsam is a fast-growing plant that is normally started indoors six to eight weeks before the last frost date. Live plants are not commonly offered in nurseries, so gardeners usually need to buy seeds. It’s recommended to pinch back the stems once the plants are around 4 inches tall to create stronger and fuller growth. Also, be aware that these flowers are quite good at self-seeding in ideal growing conditions. So be ready to pull seedlings if they spread to areas where you don’t want them. Other than that, regular watering and feeding throughout the growing season (spring to early fall) will keep your balsam flowers blooming beautifully.
Light
These flowering plants grow well in both full sun and partial shade. The best growing site offers some protection from strong afternoon sun, which can cause browning of the foliage. Balsam flowers can survive in full shade, though their blooms will likely be sparse in those conditions.
Soil
Organically rich, well-draining soil is best for balsam flowers. A loamy soil is recommended, though they also can grow in sandy and clay soils. A slightly acidic to neutral soil pH is ideal, but they can handle slightly alkaline soil, too.
Water
Keep the soil of balsam plants consistently moist throughout the growing season. They can continue to bloom even during heat waves but only if they have enough to drink. Conversely, they don’t tolerate drought well and will usually stop flowering if they don’t get enough water. Water whenever the top inch or two of soil feels dry to the touch, but avoid overwatering and allowing plants to become waterlogged.
Temperature and Humidity
Balsam flowers do not tolerate cold temperatures (32 degrees Fahrenheit or below) and are instantly killed by any hint of frost. They thrive in warm temperatures, though they can wilt in summer heat waves. Moreover, due to balsam’s water requirements, the plants also like some humidity. But they can tolerate drier air if their soil moisture needs are being met.
Fertilizer
Fertilize with a balanced, slow-release flower fertilizer during the growing season, following label instructions. It also can be beneficial for healthy growth and flowering to mix some compost into the soil at the time of planting.
Types of Garden Balsam
Rather than offering named cultivars, some garden centers and seed vendors sell garden balsam in generic mixes, identified by basic growth habit or by flower shape or color. For example, you can buy seeds for plants bred to have camellia-shaped flowers, a short, bushy growth habit, or bright carmine-red flowers. There are also several named cultivars of garden balsam available, including:
‘Blackberry Trifle’: This plant is known for its purple and white variegated petals.‘Bush Mix’: Some balsam plants can get lanky by the end of the growing season, but the ‘Bush Mix’ cultivar stays compact and full.‘Tom Thumb Mix’: Averaging 8 to 10 inches tall, this variety is ideal for the edge of a border or a container garden.
Pruning
There is no pruning necessary for the health of these plants, but pinching them back when seedlings are about 4 inches high will help them develop a more bushy growth habit. Otherwise, these plants can get overly lanky and sparse, especially in shady conditions. Carefully deadheading the individual flowers as they fade can restrict the plant’s annoying habit of aggressively self-seeding in the garden.
Propagating Garden Balsam
Garden balsam is often started from seed (see below) but it can also be propagated by rooting stem cuttings. This is often done in the fall in order to propagate new plants indoors over the winter. Here’s how to do it:
Growing Garden Balsam From Seed
Garden balsam is very easy to grow from seed, which is the way most people growthis plant, as potted nursery starts are rarely available at garden centers. Purchased or collected seeds sprout in as little as four days in moist soil at 70 degrees Fahrenheit. Start them indoors about six to eight weeks before your area’s projected last frost date, planning for about 60 days from seed to first bloom. Light hastens germination, so don’t fully cover the seeds with soil. Just gently press them into a seed-starting mix. Keep the soil consistently moist but not soggy. When outdoor soil temperatures begin to warm (usually as the average nighttime temperatures reach about 60 degrees Fahrenheit), you can bring your balsam seedlings outdoors for progressively longer stretches. Then, once frost is no longer in the forecast, plant them in a group about 1 foot apart for the greatest impact. If you want to collect seeds at the end of the season to plant in other areas, keep a baggie very close. The ripe seed heads will burst and distribute their contents everywhere when you pinch them.
Potting and Repotting Balsam
Like many annual flowers, garden balsam flowers can grow well in containers on balconies and terraces. Just make sure to use a large pot with ample drainage holes. Any good quality commerical potting mix will suffice. Plan on more frequent watering with container-grown plants, as they tend to dry out quicker than in-ground plants. Garden balsam needs at least 1 foot of space between plants. If you start out with a large enough container, repotting won’t be necessary for these annuals.
Overwintering
As a true annual, garden balsam dies out at the end of the growing season and must be discarded. You can, however, take stem cuttings and root them indoors over the winter to grow potted plants for the following spring. These do not, however, make good permanent houseplants, as they quickly fade once the long flowering season is over.
Common Pests & Plant Diseases
Though relatively free of pests and diseases, garden balsam is sometimes visited by aphids and cucumber beetles, which can be handled with a horticultural oil, such as neem oil. I. balsimina can also be susceptible to powdery mildew (not usually serious) or by the same downy mildew organism that decimated the common impatiens (I. walleriana) for many years. Should you spot signs of downy mildew, affected plants should be removed and destroyed to prevent the spread of the disease.
How to Get Garden Balsam to Bloom
Planted from seed, garden balsam will flower in just 60 days, then produce flowers all summer and into fall—until cold weather halts them. Thus, starting seeds indoors six to eight weeks before the last frost can ensure flowers from late spring onward. Unlike common impatiens, garden balsam needs a fair amount of direct sunlight in order to produce its spring-to-fall flower show. They will bloom adequately in partial shade but do not like full shade. Failure to bloom may indicate a cultural problem, such as aphid damage or fungal infection.
Common Problems With Garden Balsam
The most common complaint with garden balsam stems from the ease with which its exploding seed heads scatter seeds far and wide around the garden. Combined with its fast-growing nature, this makes garden balsam a borderline invasive plant, especially in warmer regions with long growing seasons. You can prevent this spread by carefully removing spent flowers before the seed pods mature.
