I've always wanted a dedicated 'chocolate-scented' garden. Since I'm in a fairly temperate zone of California, it's certainly possible. I've always used cocoa bean hulls as mulch, and there's nothing that smells more like chocolate than this mulch, but if you have dogs, you'll want to skip the mulch which is dangerous to dogs.
But as for real chocolate smelling plants, I've been given (and time to get more) Cosmos atrosanguineus. This is a lovely maroon cosmos that actually has a heavy chocolate scent. Originally from Mexico, this plant reblooms in the San Francisco Bay Area Mediterranean climate.
I have Chocolate mint, a very hardy perennial, well it's mint, after all. Warning: it will take over the garden. Plant in containers or monitor its spread. It doesn't taste like chocolate, but definitely smells like it.
There's a wonderful article online: Growing a Chocolate-Scented Garden by Deb Babcok in Steamboat Today. Her climate in Steamboat Springs is harsher than mine and the growing season is shorter, but she has a great list of chocolate scented plants. I decided to add to this list, so here are several plants that smell like chocolate. What could be more delightful than a chocolate garden? Be sure and check that these plants will grow and flourish in your zone. Be sure and check before planting.
Chocolate Flower (Berlandiera lyrata) Looks like a daisy with yellow petals and a dark chocolate center. The aroma from the flower can be detected as far as 30 feet away. This is a night-bloomer, so the garden will smell like cocoa in the morning.
|Nicotania Chocolate Smoke|
Decidious (to semi-evergreen) twining Chocolate Vine (Akebia Quinata): climbing plant with purple-red flowers that smell of milk chocolate. Warning: Can be invasive. Keep it trimmed.
Chocolate Mint (Mentha piperita): Some people think this tastes like a combo of chocolate and peppermint. Nice bronze-green leaves.. and as I mentioned, it can be used as a tea and as one of the main ingredients in Chocolate Mint Pots de Creme.
Delphinium "Kissed by Chocolate"
Dahlia 'Karma Choc': Not certain of the scent on this but it has a very dark color like chocolate.
Gilia tricolor (Bird's Eyes): annual California wildflower with wonderful fragrance. Meadow plantings. Grows to 3' (not for a small garden patch)
|Columbine chocolate soldiers|
Foxglove (Digitalis 'chocolate') now this is literally a Dying for Chocolate plant as foxglove is a poisonous plant also: Digitalis Lanata 'Cafe Creme'; Digitalis parviflora 'Milk Chocolate'
Nasturtium (Tropaeolum 'Chocolate')
Rudbeckia (R. 'Chocolate Drop')
Sweet William (Diantush 'Bittersweet William')
Carolina allspice (Calycanthus floridus): Deciduous shrub with maroon brown flowers (cinnamon-spiced, bittersweet chocolate fragrance)
Cosmos Astroganguineus: Plants form a medium-sized clump of dark green leaves, with deep maroon blooms that smell of dark chocolate.
|Chocolate Cherry Tomatoes|
Penstemon 'Chocolate Drop' How can you go wrong with penstemon?
One mustn't forget edible plants in the garden that smell (and sometimes taste) like chocolate:
Chocolate Corn, Chocolate Cherry Tomato, Chocolate Mini Bell Pepper, 'Velour Frosted Chocolate' Viola, Chocolate Nasturtium, and Milk Chocolate Calendula.
|Cacoa Pod - UC Botanical Garden|
Love to add to this list, so please comment on your favorite "chocolate" plants. Plants or seeds welcome.
And, here's a photo from one of the University of California Botanical Garden greenhouses of a chocolate pod. I do not have a tropical greenhouse on my property.