The Northern Catalpa tree is a medium to fast growing tree - growing 15 feet tall over a 7 to 8 year period. The Northern Catalpa Tree can reach heights of 40 to 60 feet. Spring clusters of flowers are very showy, attracting humans, insects, and hummingbirds.
Soil Type: Very tolerant of different soil conditions but prefers deep, moist, fertile soil. Withstands extremely hot, dry environments.
Zones: 4 to 9
Germination Range: 50-70%
Stratification Requirement: None required.
Indoor Planting: If your seeds require stratification or scarification – do the recommended pretreatment before planting indoors. Planting Instructions: Fill a container with seed starting mix to about ½ inch from the top. Place your seeds 1 inch to 1 ½ inches below the soil surface. Gently water your seeds to keep moist, not soaking wet. Heat & humidity is critical for germination. Germination may occur in 1 week or as long as 3 months (depending on the species). Place the seed container on a heat mat under growing light(s). Keep your growing lights on 14 hours per day. Keep your heat mat on 24 hours per day. Once your seeds germinate, move each seed into its own container under the growing lights and on the heat mat. Keep your seedlings indoors for 2-3 months before transplanting outdoors in the spring (May to June).
Outdoor Planting: If your seeds do not require stratification: the best time to plant tree and shrub seeds outdoors is after the last frost in your area (spring). In the Northern states – the best time to plant seeds outdoors is from May to June. If your seeds require pretreatment: you should plant your seeds outdoors before the ground freezes in your area (late September to early November). Your seeds will naturally stratify during the cold winter. Germination usually occurs in May or during the spring season.