Species of the Month

Poison Oak

Regular visitors of the Arboretum may be far too familiar with this month's featured species, but how much do you really know about poison oak (Toxicodendron diversilobum)?

• The genus Toxicodendron includes poison oak (eastern and western), poison ivy, poison sumac, and the lacquer tree.
• Irritation from touching these plants is a contact dermatitis caused by an oily cocktail of compounds referred to as urushiol, which comes from the japanese word for the lacquer tree, urushi
• People with strong reactions to poison oak are often also sensitive to mango skins 
• As the specific epithet - diversilobum - implies, pacific poison oak can vary greatly in the shape and size of its leaflets as well as the way in which it grows. It can grow as a vine, a shrub, or even as a tree and can have leaflets that are large or small, round, elongated, or pointed, with smooth, lobed, scalloped or toothed margins. Depending on the season and other environmental conditions, the leaves can be shiny or dull, red or green. 
• Even the rule “leaves of three, leave it be”, can’t always be trusted. The compound leaves of pacific poison oak are typically composed of three leaflets, but can also occasionally have five, seven, or even nine. 
• This phenotypic plasticity isn’t fully understood, but at least some characteristics have been found to be change in association with environmental factors such as light and water availability.
• Despite its reputation among humans, most animals do not seem to react to this important native plant. On the contrary, native deer and squirrels feed on its leaves and several species of birds consume its fruits and find shelter in its branches. 
• Not everyone is sensitive to urushiol, but sensitivities can develop after multiple exposures, so be careful. Dermatitis typically sets in within two to three days, but can take longer on the first exposure.
• The oils can also be spread by skin-to-skin (or dog-to-skin or even gear-to-skin) contact. 
• If you touch poison oak, wash the area thoroughly with soap and cool water as soon as possible. 
• Beware of bare winter twigs, which also contain the itch-inducing urushiol.

Become a Nature Guide!

Volunteers needed! Nature Guide Volunteers are trained in local ecology, working with kids, plant & animal ID, and more.

Orientation Night

Tuesday, September 9th 5:00 PM - 6:00 PM

2025-2030 Strategic Plan: Your Support Matters!

Your support matters! Our 2025-2030 Strategic Plan is our bold commitment to fostering inclusion, protecting habitats, enhancing education, and creating a vibrant future for all. None of this is possible without YOU or your support. Consider donating or becoming a member today to support our pursuit of these ambitious, inspiring goals!

Forest Ecology Workshop Series

This workshop series is presented by Rich Kelly, a retired forester, long time Arboretum member, and nature guide. 

Trees & Forests - Carbon Pools

Saturday, September 20th 9:30 AM - 12:30 PM

In this session, you will explore how trees take in carbon dioxide as they grow and how forests can store large amounts of carbon, sequestering it from the atmosphere. This workshop includes site visits to assess the carbon pools at the Arboretum, analyze the carbon stores and processes, and a look at how forests can capture carbon and mitigate climate change.

Equinox Watercolor and Creative Writing Workshop

Wednesday, September 24th 4:30 PM - 6:30 PM

Celebrate the magic of the autumn equinox with a creative and reflective family-friendly workshop lead by Clara-Julia Peru! Together, we’ll explore the beauty of native plants as they transition with the season, using watercolor painting and creative writing to connect with nature in a meaningful way. Whether you’re a budding artist, a curious writer, or simply looking for a unique way to spend time with loved ones, this workshop offers a welcoming space to create, reflect, and celebrate the equinox together.

Upcoming Nature Tours

All guided tours start at the Mount Pisgah Arboretum Education Building. Pre-registration is required. Members and kids under 4 are FREE, Non-Members $5 per person.

September Bird Tour

Sunday, September 14th 8:00 AM - 11:30 AM

Join Mieko Aoki and Julia Siporin for another monthly bird outing intended for people with all levels of birding experience. We’ll use vocalizations, habitat, and behavior clues for identification of our year-round residents and fall migrants.

Insect Tour

Sunday, September 21st 10:00 AM - 12:00 PM

Open your eyes to the fascinating world of insects on a tour led by insect-enthusiast and Mount Pisgah blog author Karen Richards. We’ll look into the incredible adaptations of some creatures you may recognize, and no doubt learn about some lesser-known insects as well. Every insect tour is a mini-safari!

Upcoming Work Parties

Become a steward of the Arboretum by helping us improve and maintain our facilities and habitat during our Work Parties! 

During Work Parties, volunteers help us keep our trails, facilities, and park clean, accessible, and beautiful! No experience is required to volunteer on these days, and we will provide tools, gloves, and a parking pass. 

For all our work parties, we will meet at the bottom of the parking lot near the shop (the string of buildings at the bottom of the lot) at 9 AM. 

Water Garden Maintenance

Saturday, September 13th 9:00 AM - 12:00 PM

Come out and help us maintain our habitats by removing woody vegetation, digging out invasives, and improving access to this area of the arboretum. No experience required.

Accessible Trail Resurfacing Project - United Way Days of Caring

Thursday, September 25th 9:00 AM - 12:00 PM

Help Mount Pisgah Arboretum keep our most loved paths accessible, attractive, and safe for all visitors! Project volunteers will help load, haul, spread and rake out trail surfacing materials (gravel for this event) on some of our most used trails.

Get Involved

Want to make a difference in other ways? We are always looking for nature guides, trail stewards, park ambassador volunteers, and many other roles. Let's talk about how you can get involved with the Arboretum.

Learn more about some of the opportunities here.