Hybrid trees result from pollinating (fertilizing) unrelated tree types within the same tree species. Pollen collected from a male tree is transferred to a female plant that then produces seeds. The new seeds carry embryonic hybridized trees with characteristics from both parents. Hybrid flowering trees may have exciting have new flower colors and forms or larger, sweeter fruit. First-generation--F1--seeds produces vigorous trees. Second-generation seeds, however, may not develop properly.
Red Horse Chestnut 'Briotii'
Red horse chestnut (A. hippocastanum x A. pavia) is an early 19th-century European horse chestnut hybrid of the horse chestnut and the flowering buckeye. It stands 25 to 35 feet high, with deep green, toothed leaves and 8-inch spikes of red mid-spring flowers. This tree is susceptible to warm weather leaf blotch.
The 1858 'Briotti' red chestnut cultivar (Aesculus x carnea) is more disease-resistant, with larger flower heads and darker blooms. Capsules containing poisonous nuts follow the flowers. These trees, says the Missouri Botanical Garden, are attractive additions to large lawns and public parks, although their leaves may brown in high-wind locations or during drought. Plant them in well-drained, moist fertile soil and sun to partial shade. Red horse chestnut's seeds are viable.
Stellar Hybrid Dogwoods
These hybrid trees are crosses of flowering dogwood (Cornus florida) and Kousa dogwood (Cornus kousa). They include six vigorous trees that produce large fragrant blooms beginning in April--when flowering dogwood's bloom is fading. Blooms conceal the trees' deep green leaves. Branches begin low on the trunks, spreading uniformly as they ascend the trees.
Stellar Pink is the only variety with pink blooms. Stardust is the smallest, standing from 8 to 12 feet high and 12 to 15 feet wide. Plant the Stellar dogwood hybrids, advises the Missouri Botanical Garden, in moist, rich acidic soil and part shade. They will benefit from cooling mulch in summer.
Saucer magnolia (Magnolia x soulangeana) is a small tree, standing between 20 and 25 feet high and wide. It usually has multiple trunks and a round form. Large, fragrant pink-tinged white blooms up to 10 inches across adorn its branches in March. Because it blooms so early, saucer magnolia does best in a location protected from frost. Some trees also produce red cone-shaped fruits that open to suspend bright red seeds from white filaments. Many saucer magnolias, however, are infertile. The Missouri Botanical Garden recommends planting this tree in full sun to partial shade and moist, rich well-drained loam.