Seeds and cuttings I collect around North Carolina, what they turned out to be, and how to grow them for a NC Piedmont native-plant nursery.
Liriodendron tulipifera · Magnoliaceae
Tallest hardwood in the Piedmont. The cones look loaded but most of the samaras are hollow, so cut-test before stratifying.
Community photos of Liriodendron tulipifera to study before I head out: leaf, flower or bract, ripe fruit, bark, whole plant.
Common to abundant throughout Person County and the entire NC Piedmont. One of the region's dominant canopy hardwoods
Best bet: Fill is the whole problem. Even the best open-pollinated trees top out near 35% filled seed per cone, and viability of dispersed seed runs just 5–20% (USFS Silvics/FEIS). A cone that looks loaded usually isn't. Hedge two ways. (1) Collect cones from several forest-grown trees rather than a lone yard specimen, since cross-pollination sharply raises fill (controlled crosses reach ~90%). (2) Verify before investing in stratification: air-dry the cones, break them into individual samaras, and cut-test a sample. Slice lengthwise and look for a plump white embryo and endosperm (filled) against a flat, hollow cavity (empty). A float test culls floaters. Cold-moist stratify filled seed 70–90 days at 32–50°F (0–10°C) in moist sand or perlite, then sow in spring, or fall-sow outdoors and let winter stratify it. Expect only 5–20% germination even with sound seed, so sow heavy. Seed banks 4–7 years, so a fall-sown flat may still surprise you the second spring.
A dominant Piedmont native, fast-growing and well-suited to Person County's deep moist soils, and not invasive. Tolerates clay if it isn't waterlogged, but young trees are drought-sensitive and will shed leaves in a dry late summer, so nursery beds and transplants need summer water. Large canopy tree, so space grow-out and final planting accordingly. Only minor pest issues (tuliptree aphid and sooty mold, yellow-poplar weevil). The real caveat sits at collection rather than grow-out: low seed fill means cut-testing and collecting from several trees is essential.
Each look-alike with the one character that settles it. Tap a photo to zoom.
Leaves are entire, unlobed ellipses, and the fruit is a knobby red 'cucumber' rather than a dry cone of samaras
Leaves palmately lobed like a maple, bark mottled and exfoliating white-and-tan, fruit a hanging round ball
Star-shaped leaf with 5–7 palmate lobes and a spiky gumball fruit, against tulip tree's 4-lobed flat-topped leaf and erect samara cone
Leaves and buds strictly opposite. Tulip tree is alternate, with a valvate duck-bill bud
Tulip tree is easy. It's usually the tallest, straightest tree in the stand, an arrow-clean bole rising above everything else on mesic lower slopes, coves, and old-field forest. What I look for depends on the month. April through June, look up for the greenish-yellow tulip flowers with an orange base band, high in the canopy. In October the whole crown turns a clean buttery yellow that pops out of the mixed hardwoods. From October into winter the twigs hold erect, straw-brown cone-like fruits standing upright like candles. And on the ground the 4-lobed, flat-topped cat-face leaf litters the trail. Nothing else in these woods has that leaf.
Collect whole straw-brown cones in October and November, once they're ripe. Green cones are immature, and since the samaras persist on the twig into winter there's a wide window. Here's the catch this guide exists for: the cones look loaded but are mostly empty. Per USFS Silvics, even the best open-pollinated trees top out around 35% filled seed per cone, and viability of the seed that disperses runs only 5–20%. A cone in the hand tells me almost nothing about how much live seed I'm holding.
So hedge two ways. First, collect from several forest-grown trees rather than a lone yard specimen. Cross-pollination raises fill dramatically; controlled crosses hit around 90%. Second, verify fill before investing in stratification. Air-dry the cones, break them into individual samaras, and cut-test a sample: slice a samara lengthwise and look for a plump white embryo and endosperm (filled) versus a flat, hollow cavity (empty). A quick float test culls floaters.
Then cold-moist stratify the good seed 70–90 days at 32–50°F (0–10°C) in moist sand or perlite and sow in spring, or fall-sow outdoors and let the Piedmont winter do the chilling. Even with sound seed germination runs a low 5–20%, so sow heavy. Seed can bank in the soil for 4–7 years, so a fall-sown flat may surprise me the second spring. Cuttings historically fail, so seed is the route.
Around Roxboro and Person County, work the mesic slopes and bottomland edges at Mayo Lake Park and along Hyco Lake. Farther out it's abundant in Duke Forest, Eno River State Park, and Umstead State Park, anywhere with moist deep soil and a recovering hardwood canopy.