Catalpa speciosa
Northern Catalpa, Early Flowering Catalpa, Hardy Catalpa, Western Catalpa, Indian Cigar, Shawnee Wood
Northern Catalpa, Early Flowering Catalpa, Hardy Catalpa, Western Catalpa, Indian Cigar, Shawnee Wood
Type Tree, woody plant
Hardy range 4B to 9A
Height 35' to 70' / 10.60m to 21.40m
Spread 35' to 45' / 10.60m to 13.80m
Growth rate Fast
Form Oval
Exposure Partial shade or partial sun to full sun
Persistence Deciduous
Hardy range 4B to 9A
Height 35' to 70' / 10.60m to 21.40m
Spread 35' to 45' / 10.60m to 13.80m
Growth rate Fast
Form Oval
Exposure Partial shade or partial sun to full sun
Persistence Deciduous
Bloom Color White
Bloom Time Spring and Summer
The flowers are very showy.
Bloom Time Spring and Summer
The flowers are very showy.
Environment
This plant tolerates drought and occasional wetness.
This plant will grow in very dry to occasionally wet soil.
Suitable soil is well-drained/loamy, sandy or clay.
The pH preference is an acidic to alkaline (less than 6.8 to more than 7.7) soil.
This plant tolerates drought and occasional wetness.
This plant will grow in very dry to occasionally wet soil.
Suitable soil is well-drained/loamy, sandy or clay.
The pH preference is an acidic to alkaline (less than 6.8 to more than 7.7) soil.
Leaf Color Green
Fall Color Yellow
Fall Color Yellow
Culture Notes
Northern Catalpa tolerates a wide range of soils, including pH in the 7's, and is moderately drought-tolerant. It is a tough tree suited for planting in large-scale landscapes. Catalpa often escapes cultivation and invades surrounding woodlands. It is a tough plant that can grow about any place including sidewalk cutouts and could be used more. Catalpa speciosa grows in a loose oval, 50 feet tall in most urban locations, but occasionally grows to 90 feet. Plants in containers tolerate moderate soil salt solutions up to about 4 mmhos/cm according to the saturated media extract method.
This coarse, large leafed tree spreads 45 feet and tolerates hot, dry weather, but leaves may scorch (especially cultivars with variegated foliage) and some drop from the tree in very dry summers. Expect one and two year old twigs on the ground after a summer thunderstorm or following windy weather. Fruit litter the ground in spring. The pretty flowers are produced a couple of weeks before C. bignonioides and they attract bees. One reference says pollen can cause significant allergies; another one says they do not cause allergies.
Wood was used for railroad ties and fence posts in times past.
Plants can be cut back to the ground each year to act like a perennial. The vigorous growth produces large leaves and a rich tropical effect in the shrub border.
Tree establishment specifications
Choose good quality trees for planting. The most common cause of young tree failure is planting too deep. In most instances, the point where the top-most root in the root ball originates from the trunk (referred to as the root flare zone or root collar) should be located just above the soil surface. You may have to dig into the root ball to find the root flare. If there is nursery soil over this area, scrape it off. Never place ANY soil over the root ball. The planting hole should be at least twice the width of the root ball, preferably wider because roots grow best in loose soil. In all but exceptional circumstances where the soil is very poor, extensive research clearly shows that there is no need to incorporate any amendments into the backfill soil. Simply use the loosened soil that came out of the planting hole. Simply planting with the topmost portion of the root ball slightly higher than the surrounding soil might still install the tree too deep - be sure to locate the root flare.
Weed suppression during establishment is essential. Apply a 3-inch thick layer of mulch to at least a six-foot diameter circle around the tree. This area should be at least two feet in diameter for each inch of tree trunk diameter and maintained during the establishment period. Apply a thinner layer of mulch directly over the root ball but keep it at least 10 inches from the trunk. This allows rainwater, irrigation and air to easily enter the root ball and keeps the trunk dry. Placing mulch against the trunk and applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water.
Regular irrigation after planting encourages rapid root growth that is essential for tree establishment. Trees provided with regular irrigation through the first growing season after transplanting require about 3 months (hardiness zones 9-11), 6 months (hardiness zones 7-8), or one year or more (hardiness zones 2-6) per inch of trunk diameter to fully establish roots in the landscape soil. Trees in desert climates may take longer to establish. Trees that are under-irrigated during this establishment period (and most trees are) often require additional time to establish because roots grow more slowly. Be prepared to irrigate through the entire establishment period, especially during periods of drought.
Irrigation also helps maintain and encourage the desirable dominant leader in the tree canopy on large-maturing trees. Instead of a dominant leader, trees that are under-irrigated during the establishment period often develop undesirable, low, co-dominant stems and double leaders that can split from the tree later.
Unlike established plants, which do best with deep, infrequent irrigation, research clearly shows that recently transplanted trees and shrubs establish quickest with light, frequent irrigation. For trees planted in spring or summer, provide one (cooler hardiness zones) to three irrigations (warmer hardiness zones) each week during the first few months after planting. Daily irrigation in the warmest hardiness zones provides the quickest establishment. Following the initial few months of frequent irrigation, provide weekly irrigation until plants are fully established. With every irrigation, apply one (cool climates) to two (warm climates) gallons of water per inch trunk diameter (e.g. 2 to 4 gallons for a 2-inch tree) over the root ball only. In most landscapes that receive more than 30 inches of rain or irrigation annually, if the mulch area is maintained weed-free, irrigation does not need to be applied outside of the root ball. Never add water if the root ball is saturated.
In cooler hardiness zones, in all but the driest years, irrigation of spring- and summer-planted trees usually can be discontinued once fall color has begun. Irrigation of fall planted trees, however, should be continued until foliage has dropped from the deciduous trees in the region. In warmer climates, irrigate fall-and winter-planted trees as described for the spring- and summer-planted trees.
In drier, desert climates there is benefit to be gained from applying additional irrigation outside of the root ball area. This is best done by making a large diameter berm four to six inches high, then filling it with water so it percolates into the soil. For the first two years, irrigate twice each week through the spring, once per week in summer provided monsoons arrive, and twice each week again in fall if it remains warm. Taper off watering to once or twice each month in winter and resume twice weekly next spring. For years three to five, water twice per month in spring, summer, and fall and once or twice per month in winter. During years five through seven, water once every three weeks in warm weather and once every six weeks in winter. After this, the drought-tolerant desert trees should be able to survive on natural rainfall.
Trees with good, strong structure need no pruning at planting, except to remove broken twigs. Do not remove branches to compensate for root loss - research has shown that this can be detrimental to establishment.
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Northern Catalpa tolerates a wide range of soils, including pH in the 7's, and is moderately drought-tolerant. It is a tough tree suited for planting in large-scale landscapes. Catalpa often escapes cultivation and invades surrounding woodlands. It is a tough plant that can grow about any place including sidewalk cutouts and could be used more. Catalpa speciosa grows in a loose oval, 50 feet tall in most urban locations, but occasionally grows to 90 feet. Plants in containers tolerate moderate soil salt solutions up to about 4 mmhos/cm according to the saturated media extract method.
This coarse, large leafed tree spreads 45 feet and tolerates hot, dry weather, but leaves may scorch (especially cultivars with variegated foliage) and some drop from the tree in very dry summers. Expect one and two year old twigs on the ground after a summer thunderstorm or following windy weather. Fruit litter the ground in spring. The pretty flowers are produced a couple of weeks before C. bignonioides and they attract bees. One reference says pollen can cause significant allergies; another one says they do not cause allergies.
Wood was used for railroad ties and fence posts in times past.
Plants can be cut back to the ground each year to act like a perennial. The vigorous growth produces large leaves and a rich tropical effect in the shrub border.
Tree establishment specifications
Choose good quality trees for planting. The most common cause of young tree failure is planting too deep. In most instances, the point where the top-most root in the root ball originates from the trunk (referred to as the root flare zone or root collar) should be located just above the soil surface. You may have to dig into the root ball to find the root flare. If there is nursery soil over this area, scrape it off. Never place ANY soil over the root ball. The planting hole should be at least twice the width of the root ball, preferably wider because roots grow best in loose soil. In all but exceptional circumstances where the soil is very poor, extensive research clearly shows that there is no need to incorporate any amendments into the backfill soil. Simply use the loosened soil that came out of the planting hole. Simply planting with the topmost portion of the root ball slightly higher than the surrounding soil might still install the tree too deep - be sure to locate the root flare.
Weed suppression during establishment is essential. Apply a 3-inch thick layer of mulch to at least a six-foot diameter circle around the tree. This area should be at least two feet in diameter for each inch of tree trunk diameter and maintained during the establishment period. Apply a thinner layer of mulch directly over the root ball but keep it at least 10 inches from the trunk. This allows rainwater, irrigation and air to easily enter the root ball and keeps the trunk dry. Placing mulch against the trunk and applying too thick a layer above the root ball can kill the plant by oxygen starvation, death of bark, stem and root diseases, prevention of hardening off for winter, vole and other rodent damage to the trunk, keeping soil too wet, or repelling water.
Regular irrigation after planting encourages rapid root growth that is essential for tree establishment. Trees provided with regular irrigation through the first growing season after transplanting require about 3 months (hardiness zones 9-11), 6 months (hardiness zones 7-8), or one year or more (hardiness zones 2-6) per inch of trunk diameter to fully establish roots in the landscape soil. Trees in desert climates may take longer to establish. Trees that are under-irrigated during this establishment period (and most trees are) often require additional time to establish because roots grow more slowly. Be prepared to irrigate through the entire establishment period, especially during periods of drought.
Irrigation also helps maintain and encourage the desirable dominant leader in the tree canopy on large-maturing trees. Instead of a dominant leader, trees that are under-irrigated during the establishment period often develop undesirable, low, co-dominant stems and double leaders that can split from the tree later.
Unlike established plants, which do best with deep, infrequent irrigation, research clearly shows that recently transplanted trees and shrubs establish quickest with light, frequent irrigation. For trees planted in spring or summer, provide one (cooler hardiness zones) to three irrigations (warmer hardiness zones) each week during the first few months after planting. Daily irrigation in the warmest hardiness zones provides the quickest establishment. Following the initial few months of frequent irrigation, provide weekly irrigation until plants are fully established. With every irrigation, apply one (cool climates) to two (warm climates) gallons of water per inch trunk diameter (e.g. 2 to 4 gallons for a 2-inch tree) over the root ball only. In most landscapes that receive more than 30 inches of rain or irrigation annually, if the mulch area is maintained weed-free, irrigation does not need to be applied outside of the root ball. Never add water if the root ball is saturated.
In cooler hardiness zones, in all but the driest years, irrigation of spring- and summer-planted trees usually can be discontinued once fall color has begun. Irrigation of fall planted trees, however, should be continued until foliage has dropped from the deciduous trees in the region. In warmer climates, irrigate fall-and winter-planted trees as described for the spring- and summer-planted trees.
In drier, desert climates there is benefit to be gained from applying additional irrigation outside of the root ball area. This is best done by making a large diameter berm four to six inches high, then filling it with water so it percolates into the soil. For the first two years, irrigate twice each week through the spring, once per week in summer provided monsoons arrive, and twice each week again in fall if it remains warm. Taper off watering to once or twice each month in winter and resume twice weekly next spring. For years three to five, water twice per month in spring, summer, and fall and once or twice per month in winter. During years five through seven, water once every three weeks in warm weather and once every six weeks in winter. After this, the drought-tolerant desert trees should be able to survive on natural rainfall.
Trees with good, strong structure need no pruning at planting, except to remove broken twigs. Do not remove branches to compensate for root loss - research has shown that this can be detrimental to establishment.
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