Pressing Matters: How to Press a Plant for an Herbarium

Interested in making an herbarium specimen?  There are a few things to keep in mind, and a few materials you’ll need.

Keep in mind:
Be sure you have permission to collect from the place where the plant grows.
An herbarium specimen is mounted on paper which is 11.5″ wide by 16.5″ long — so a specimen can be no bigger than that.  If a plant is 5 feet tall, you will have to cut it into segments, each no longer than 16″!
ONLY you know where you collected the plant.  Accurate locality information is vital.  You, alas, are not famous enough for “my back yard” to be sufficient locality data.  Poorly pressed specimens or specimens lacking sufficient information on locality will be rejected by the Curatrix.

Things you’ll need:
single folds of newspaper, cut to 16″ in length, one fold for each plant
a pen to write on the newspaper
optional but handy:  a trowel, and perhaps a set of garden shears / scissors (depending on size of plant)
2 pieces of corrugated cardboard per plant specimen, the cardboard cut into rectangles 11″ X 16″
optional but very helpful:  foam rubber, cut into rectangles 11″ X 16″
a stack of heavy books (or a plant press with straps)
optional but very helpful:  a smart phone which gives latitude/longitude coordinates or has iNaturalist app.

Items you need: corrugated cardboard (2 per specimen) cut to about 11″ X 17″, a single fold of newspaper (cut to 11 X 17). Optional but extremely useful: foam rubber cut to 11″ X 17″. An herbarium sheet is a cubit in length = the length from your fingertips to your elbow.


It is very handy to have a compass on your smart phone which can provide latitude/longitude of your collecting location.


I use the app iNaturalist (free!) on my smart phone to take photos of the plants I collect and to get the latitude/longitude of the location.



Collect plant — use trowel or garden shears if necessary. Remember your specimen or specimen segment should be less than 16″ long.  (If a shrub or tree, a branch about 16″ long with flower/fruit.)


On a single fold of newspaper write date, plant name, location, collector name. Use merely a SINGLE fold of newspaper — more prevent the plant from drying.
Note that I have bent the longest flowering stem so that it fits in the newspaper, and ultimately will fit onto the herbarium sheet.



Close sheet of newspaper over your plant and place sheet of foam rubber on top. This will endure that the thicker portion of the plant (typically roots or twigs) do not impede the complete pressing of thinner portions of plant (typically leaves and flowers).


I decided to press a second specimen — a sterile basal rosette which was growing nearby. Again, label single fold of newspaper with information.


Place specimen in single fold of labeled newspaper.


Double decker sandwich: corrugated cardboard, plant in single newspaper fold, foam rubber, corrugated cardboard (repeat as needed!)


Place plants in press and tighten straps. Children are particularly enthusiastic about standing on the press so you can tighten straps further.


Fear Not! If you do not have a plant press, a stack of hefty books placed on your cardboard-plant sandwich will suffice. Leave in an air conditioned place for a month or so.


Once your plant(s) have dried, remove the foam rubber and save for future pressing needs. Compose a “working label” with collection date, location, plant name, collector(s) names, and habitat data. Slip a working label in side EACH plant. The Herbarium staff will use this working label to compose a label printed on 100% cotton, acid-free archival paper for the specimen. Note Ms. Dill’s excellent information and legible handwriting!!


Use masking tape or duct tape to bundle the cardboard plant sandwiches together — use enough cardboards so the package is rigid. Wrap in paper (I use paper shopping bags!) and mail to: Herbarium, CB 3280 Coker Hall, 120 South Rd, University of North Carolina at Chapel Hill, Chapel Hill NC 27599-3280. Use whatever shipping method you prefer — speed is not necessary.