fall color guaranteed

American sweetgum at Stoneleigh

By Kit Werner

Before we talk about autumn’s arboreal display, let’s have a mini science lesson.

There are several types of pigment in leaves:

• Chlorophyll (green)
• Xanthophylls (yellows)
• Carotenoids (oranges)
• Anthocyanins (reds)
• Tannins (browns)

These pigments are always present in the trees’ leaves but are hidden by green chlorophyll spring and summer. In fall, shorter days and less sunlight are signals for trees to stop making chlorophyll and prepare for dormancy. As the green fades, the reds, oranges, and yellows become visible. Because they do not fade, brown tannins are the last colors to remain in a leaf before it falls.

Peak leaf peeping in southeastern Pennsylvania generally occurs in mid-October, though weather impacts both timing and the intensity of the color display. However, there are some native plant species that never fail to deliver vibrant fall leaf color, regardless of drought, deluges, and cold snaps. Here are a few of our favorites:

Trees:

• Black gum (Nyssa sylvatica)
• Pawpaw (Asimina triloba)
• Smoketree (Cotinus obovatus)
• Sourwood (Oxydendrum arboreum)
• American Sweetgum (Liquidambar styraciflua)
• Flowering Dogwood (Cornus florida)

Shrubs:

• Virginia Sweetspire (Itea virginica)
• Witch-Alder (Fothergilla spp.)
• Sumac (Rhus spp.)

Perennials/Vines:

• Bluestar (Amsonia hubrichtii)
• Spotted Cranesbill (Geranium maculatum)
• Virginia Creeper (Parthenocissus quinquefolia)

Happy fall, y’all! Now get out there into the woods and enjoy the autumn show while it lasts.