Not long after florist Gayle Nicoletti designed the wedding flowers for Cupcakes and Cashmere's Emily Schuman last spring, she held a workshop that focused on a more informal theme: how to make bouquets from the things growing in your backyard—or rather, in her backyard.

Ms. Nicoletti invited a group of 20 women to her Mill Valley, CA home the other day for a lesson in creating spontaneous flower arrangements. Here are some of her secrets:

Photographs by Kathleen Harrison.

Above: "Walk around your garden and snip flowers and herbs, and think of the arrangement you're about to make as a physical representation of that garden—what grows together? What's tall, and what's short?" says Ms. Nicoletti. From her garden: scabiosa pods (R), decorative kale (L), and succulents, including her favorite echeveria 'Metallica' (" I love the shape, like a rose, and that color —a hint of pink").

Above: Ms. Nicoletti with a flat of Sagina subulata (Scotch Moss) that she bought at Green Jeans Garden Supply in Mill Valley; it's widely available at nurseries. Ms. Nicoletti uses it to completely fill the surface of a planter to create a simple arrangement that looks like a tabletop lawn.

Above: Succulents generally don't have long stems like the rest of the flowers in a bouquet; Ms. Nicoletti attaches a false stem, wiring a viburnum twig to a succulent using florists' wire.

Above: A spool of bind wire, made in France and purchased at the San Francisco Flower Mart. A 70-foot spool of Bark Colored Wire is $8.49 from Afloral. Ms. Nicoletti uses a heavier green wire—such as Paddle Wire ($1.89 per spool from Afloral) to pierce the stem of the succulent; she twists the green wire like a pipe cleaner and attaches it to the viburnum stem.

Above: Dahlias from Ms. Nicoletti's garden. They're 'Jersey's Beauty,' an heirloom dahlia from the 1920s; bulbs are three for $39.50 from Old House Gardens.

Above: The finished bouquet, in a wide-mouthed mason jar, also includes roses, miller, and buddleia from Ms. Nicoletti's garden. For beginners, Ms. Nicoletti recommends: "Keep it simple: limit yourself to two or three different flowers and two different foliages."

Above: Parsley allowed to go to seed and flower (L) is a good addition to simple bouquets. Other favorite herbs: dark purple and black basil, for the distinctive leaves. Ms. Nicoletti also recommends getting a hydrangea bush—a 'Pistachio' Reblooming Hydrangea ($24.99 from Spring Hill) is about to go into the ground at her house—because the blooms are versatile. "You can use them alone in a vase, or mix them, or dry them," she says.

For more DIY bouquet inspiration, find out how to grow your own wedding flowers.