Most patent search sites do a poor job of presenting plant patents. The University of Maryland has a site specifically for searching US plant patents with color pictures and classification searchers. Unfortunatetly it doesn't seem to have been updated in several years.
NC State has information on plant patents but most links are back to the USPTO.
Another non-comprehensive site is at the NYC library https://www.nypl.org/node/316959. Only goes to 2018.
At the University of Maryland site You can input terms like "rose" "red" and "nut" but a better way to search is by classification. The plant classes are listed in a hierarchical manner at the USPTO. You can contract and expand the subclasses. The top level is -
152 NUT (INCLUDING ORNAMENTAL VARIETY)
156 FRUIT (INCLUDING ORNAMENTAL VARIETY)
216 BROADLEAF TREE
226 SHRUB OR VINE
258 COMMERCIAL HERBACEOUS VEGETABLE OR HERB PLANT
263.1 HERBACEOUS ORNAMNENTAL FLOWERING PLANT (NICOTINIA, NASTURTIUM, ETC.)
373 HERBACEOUS ORNAMENTAL FOLIAGE PLANT
As an example PLT/106 is -
106 Salmon: This subclass is indented under subclass 102. Shrub
rose characterized by blossoms which are salmon (a color which is
reddish red-yellow, of medium saturation and high brilliance), as
typified by U.S. plant patent No. 7312.
It is under 102 which are shrubs under 150 which are roses. So 106 are salmon colored rose scrubs.
There are only 17 total patents in class 106. The most recent is PP33,152 Rosa plant named
RUIRI0091A issued in June 2021.