Tulip trees (Liriodendron tulipifera) are fall-foliage stars that get their name from the resemblance their flowers bear to the classic tulip flower. Native to Eastern North America and the state tree of Kentucky, Tennessee, and Indiana, tulip trees or yellow poplars are tall, straight deciduous trees with a narrow crown that spreads with age. These fast-growing trees are easily identified by their spring flowers and showy leaf shape.
The flowers are yellowish-green, with a touch of orange on the outside. The smooth green leaves are broadly lobed and turn vivid golden yellow in fall. The trees are best planted in early spring once the final frost has passed. They'll grow rapidly at first (more than 25 inches a year), then slow as they get older. In the spring, the tulip tree draws pollinators like hummingbirds and bees to the nectar in its flowers, while bobwhites, rabbits, squirrels, and other animals prefer to feed on the seed. The cone-like fruit the blooms leave behind also adds ornamental value.
|Common Name||Tulip tree, tulip poplar, yellow poplar|
|Botanical Name||Liriodendron tulipifera|
|Mature Size||70–130 ft. tall, 30–60 ft. wide|
|Soil Type||Moist, well-drained|
|Soil pH||Acidic, neutral, alkaline|
|Flower Color||Yellow, green, orange|
|Hardiness Zones||4–9 (USDA)|
|Native Area||North America|
Tulip Tree Care
Tulip trees have a storied history—in fact, you've probably seen them numerous times and not even recognized them, as they don't bloom until mature, at which point the flowers are so high up in the tall tree that they can barely be seen. A member of the Magnolia family, tulip trees are known for their massive height and sturdy wood. Early settlers used yellow poplar for railroad ties and fence posts. Favored by Native Americans and explorer Daniel Boone for making canoes, George Washington even planted several tulip trees at Mount Vernon.
Tulip trees can be purchased from a local nursery and planted any time between spring and early fall. They'll fare best in a sunny spot in moist, well-drained, compost-amended soil. Bark mulch or wood chips will protect their shallow roots and help to keep the soil moist—young trees need lots of water.
Size is a factor in deciding where to plant your tulip tree: They can reach 90 feet or more in height, with a canopy width just under one half their height at maturity. The branches begin rather far up the straight trunk and are often arranged symmetrically. However, the trade-off for their fast growth is relatively weak limbs, which can create a hazard in storms.
Tulip tree will either get to its full width or full height, but not both. Trees with full access to the sun will reach full width and stay shorter, and trees with less access to the sun will grow taller and less wide.
Tulip trees prefer full sun or partial sun. Full shade can stunt the tree's growth and cause its leaves to turn brown. The sunnier the area where you plant your tulip tree, the better.
These trees prefer slightly acidic, well-drained, deep soil amended with plenty of compost. They can thrive, though, within a pH range of 5.0 to 8.0. Tulip trees can handle clay, sandy, or loamy soils as long as the soil doesn't hold water too long.
As you get your tree started, water it regularly during dry, hot spells and keep an eye on its leaves. If you notice the leaves drop earlier than usual (early fall is typical), this could indicate the tree is not getting enough water.
Temperature and Humidity
Tulip trees like a temperate climate, which is why it can typically be found in the Eastern United States. While it prefers normal moisture levels, it can tolerate drought in locations with high humidity.
Granular, liquid, or stake type fertilizers are recommended for tulip trees. For the amount to use, follow the product label instructions. Newly planted trees respond well to fertilization, but older trees generally don't require it. However, nitrogen fertilizers should not be used on newly planted trees.
Types of Tulip Tree
Tulip trees are sometimes referred to as "tulip poplar" and "yellow poplar" trees, perhaps because their leaves shake in the breeze like those of poplars. However, they are not poplars at all and instead belong to the Magnoliaceae family. Cultivars of tulip trees include:
- 'Emerald City': Darker green foliage, upright, oval growth reaching 55 feet high and 25 feet wide
- 'Little Volunteer': A dwarf cultivar, growing just 30 to 35 feet high and 18 to 20 feet wide; features smaller leaves
- 'Arnold': Narrow form with columnar crown, early to flower
- 'Fastigiatum': Upright, narrow form growing to 40 feet high and 15 feet wide
Pruning Tulip Trees
Because tulip trees grow so fast, pruning is imperative in order to keep them shapely and controlled. Their large branches are not particularly sturdy and can pose a hazard. Remove dead or weak growth in late winter and early spring, and do a thorough thinning every few years.
Propagating Tulip Trees
If you choose not to purchase your tulip tree from a nursery, you can instead propagate one using cuttings from a mother tree by following these steps:
- Take cuttings in the fall, selecting branches that are at least 18 inches or longer. Cut the branch just outside of the swollen area where it attaches to the tree.
- Place the cuttings in a bucket of water with rooting hormone added, following the directions on the label.
- When you're ready to propagate, line a planter bucket with burlap and fill it with potting soil. Plunge the cut end of the branch approximately eight inches into the soil, then cover the cutting with plastic to hold in the humidity.
- Place the bucket in a protected area that gets bright, indirect light. Check for root development a few weeks later. Your tulip tree should be ready for transplanting by spring.
Tulip trees attract tulip tree scales and tulip tree aphids. Their feeding produces honeydew which can lead to sooty mold. These pest are temporary and rarely require control measures.
The wood of the tulip tree is very soft and the twigs, limbs, and branches are prone to breakage, especially in a windy location.
Tulip trees can be messy, as their flower petals will litter the area below just after blooming. The trees are also notorious for dropping sticky sap, so avoid planting a tulip tree near an area where cars will be parked—it's no fun trying to remove the sap from a car windshield.
Is a tulip tree a good tree?
In terms of biodiversity, it is a valuable tree because as a native plant it attracts pollinators and provides food for wildlife. On the downside, it grows very fast and can quickly get too big for the average back yard. In strong winds, the branches can break off and become a hazard.
Do tulip trees smell?
The tulip-shaped flowers are fragrant. Being in the magnolia family, they have a spicy smell like a magnolia.
Is the tulip tree toxic?