Lobelia is a genus of about 370 species of annuals, perennials (even some aquatics) and shrubs. They are all basically perennials, but some are treated as annuals. In their native habitat they may be found along riverbanks, wet meadows, marshes, woodlands, mountain slopes and deserts.
Lobelias have few pest problems, but mites are among the worst. Mites feed on leaves, sucking the juices out of individual cells, which results in cell death and leaves tiny, brown spots on leaf surfaces. These larvae bore a hole in the base of lobelia Read more
One of the most common issues that can halt lobelias to flower in the summer is when they experience drought. To anticipate this, water them deeply and mulch to conserve soil moisture. You also want to check the plants regularly for pests like spider mites, Read more
In warmer zones, annual Lobelia can remain outdoors and will continue to bloom if cut back. Eventually, the plant will die out but should reseed. Even overwintering Lobelia plants indoors is no guarantee they will re-bloom in spring since these are short lived plants.
White Lobelias do not typically require deadheading, but if they start getting leggy or stretched out, feel free to trim the flowers and foliage back to promote growth. Be sure to fertilize regularly.
Plant Description Lobelia is an attractive annual or sometimes biennial (reseeding every year or 2) herb that grows to a height of 3 feet. Its upright, hairy stem is angular, branching at the top, usually green with a tinge of violet.
Lobelia is an easy-to-grow, carefree plant that enjoys cool weather. This summertime bloomer will continue to produce flowers on up through the first frost. Growing lobelia is an asset to the garden.
If you can find some new growth stems on your lobelia, choose a 4-5-inch stem, one with three or four nodes (these are the buds where the leaves emerge). Push the cuttings into a wet potting soil, leaving about half the stem above the soil. Read more
Powdery mildew is a very common disease that affects many plant types. This white coating over leaves spreads quickly and causes them to shrivel and fall off. At first glance, it may look like the leaves are covered in talcum powder, but it is actually Read more
Lobelia seeds can be sown directly in the garden or indoors for later transplanting. These plants typically require an area with full sun but will tolerate partial shade. They also prefer moist, rich soil. After all danger of frost is gone and the plants are Read more
Growing Lobelia Plant Lobelia seeds can be sown directly indoors. These plants typically require an area with full sun but will tolerate partial shade. They also prefer moist, rich soil. Start indoors about 10 to 12 weeks prior to the last frost in your region.
Perennial lobelias Lobelia cardinalis is best grown in sun or partial shade. It needs very moist, fertile soil that doesn't dry out. Lobelia tupa is best grown in full sun in a sheltered spot and fertile, well-drained soil. It may need protection in hard winters.
Lobelia erinus is the annual, producing masses of flowers throughout the summer and well into autumn until the first severe frosts.
Perennial lobelia Lobelia tupa needs a sheltered position in full sun and a good, fertile, well-drained soil.
As predicted, Lobelia spicata shares many characteristics with L. cardinalis and L. siphilitica. This species is xenogamous and self-compatible.
Lobelia cardinalis is best grown in sun or partial shade. It needs very moist, fertile soil that doesn't dry out. Lobelia tupa is best grown in full sun in a sheltered spot and fertile, well-drained soil.
Give the plant a light trim with a pair of scissors when it needs a bit of tidying. This includes trimming to remove spent blossoms. For spiky types, wait until the entire spike has faded before clipping out the stems. Cut back the plant by Read more
Lobelia erinus does not like hot, dry weather. They will grow best in a cool spot with partial shade.
Cutting back a lobelia plant will increase the blooming season and increase the number of new blossoms. Pinch back the tips of the young lobelia plants when you purchase them from the nursery. Without this initial pinching, the stems can grow long and make the Read more
Lobelia can also be grown as a perennial where winter temperatures remain above freezing. In both the upright and trailing forms, mature dimensions are typically four to nine inches tall with a spread of eight to 16 inches.
Place them in a warm, well-lit area. The seedlings should pop up within a week or two, at which time you can begin thinning them out. After all danger of frost is gone and the plants are at least 2 to 3 inches (5-7.5 cm.) Read more
Annual and perennial lobelia adapt to nearly any type of moist, well-drained soil. However, lobelia performs best in slightly acidic soil with a relatively low pH between 5.5 and 6.5.
Because of its eye-catching blue flowers, lobelia has enjoyed relative popularity amongst gardeners across the world. However, pet owners should be aware that the plant contains toxins which can be harmful to humans and animals alike. Felines can be especially badly affected if they eat Read more
Cut back the plant by half or more at the end of its bloom period. Trimming back lobelia plants keeps them from looking messy, and it may encourage another flush of blooms.
Pests and Disease Fungal problems and pests can be responsible for browning as well, especially if they feed inside the plant or directly from cells. Rust is a common external fungus on lobelia. This disease usually starts on leaf tissues, quickly covering them in orange, Read more
Lobelia in winter will die back no matter which variety you have. However, the annual Lobelia may not come back at all even if it formed seed. The annual forms tend to get weedy when temperatures get hot in summer but can be rejuvenated by Read more
Cool-season bloomers larkspur (Consolida), sweet William (Dianthus), snapdragon (Antirrhinum majus), sweet alyssum (Lobularia maritima) and lobelia (Lobelia erinus) all are reported to be deer resistant annuals. It's not surprising that deer dislike nasturtium, with its peppery flavors.
Too Much Heat. Lobelia blooms very well during cool spring weather, usually between early and late spring, but it will begin to die back during the hotter days of summer. It does not like high heat or humidity and may cease flowering during this type Read more
Growing Lobelia Plant Lobelia seeds can be sown directly in the garden or indoors for later transplanting. These plants typically require an area with full sun but will tolerate partial shade. They also prefer moist, rich soil.
Lobelia spicata Lam. This prairie perennial tends to be short-lived and does not have an obvious floral scent. Visitors to the small white flowers seek their nectar. Pollination is mostly carried out by hummingbirds and long-tongued bees.
Furthermore, lobelia is known to induce vomiting and can be poisonous — even fatal — in very high doses. Taking 0.6-1 gram of the leaf is said to be toxic, and 4 grams may be fatal (1, 16, 17).
Too Little Water. During warm weather, lobelia leaves and flowers can dry out. If the dehydration is too severe, the plant may die. Water your lobelia in pots consistently so the soil stays moist and never draws away from the side of the container.
Fertilize to Promote Healthy Blooms Annual and perennial lobelia varieties benefit from application of a dry, 5-10-10 or 5-10-5 fertilizer at planting time. Dig the fertilizer into the ground at a rate of about 5 pounds per 100 square feet of planting space. Repeat every Read more
These slimy pests love our gardens because we want to grow what they love to eat. Slugs and snails feed by rasping with their radula (a tongue-like organ covered with tiny teeth). When slugs or snails eat the outer layers (here on Lobelia cardinalis), weakened Read more
Planting lobelia Bedding plants should be planted out at the end of May or early June, after the fear of any frosts. If you have a greenhouse or other protected growing area, you can plant up containers and hanging baskets earlier for the plants to Read more
These plants typically require an area with full sun but will tolerate partial shade. They also prefer moist, rich soil. Start indoors about 10 to 12 weeks prior to the last frost in your region. Spread the tiny seeds just on top of the soil Read more
This fungus occurs everywhere and commonly infects senescing or damaged plant parts such as old flowers, causing a fuzzy gray mold. Spores are produced which are easily blown around. From these tissues the fungus moves into healthy stems and leaves, causing a damaging blight.
Pinching plants means taking off the tips and top two leaves of tender, young growth. It encourages bushy growth and better flowering. Trimming back lobelia plants keeps them from looking messy, and it may encourage another flush of blooms.
Lobelia is considered a potentially toxic herb. It can cause serious side effects, such as profuse sweating, nausea, vomiting, diarrhea, tremors, rapid heartbeat, mental confusion, convulsions, hypothermia, coma, and possibly even death.