Gardens can create surprises!
A recent surprise in my garden was the first appearance of a striking blossom that I had not seen previously and did not expect.
The blossom was from a plant called the pineapple mountain (Ochagavia litoralis), a Chilean plant in the bromeliad plant family (Bromeliaceae), which includes some 80 genera and 3,700 species, including the pineapple. The Chilean common name of my plant is chupón, which refers to any bromeliad.
This plant has been in my garden since 2018. During those years, it formed several pups, and now, in September 2025, it blossomed for the first time. I learned from interest searching that these plants don’t flower every year and might flower on alternate years. Some growers speculate that cooler temperatures trigger bloom.
The local summer climate has been cooler than in previous years, despite the longer view of climate change, so that hypothesis has some traction.
After the bloom fades, we will divide and replant the numerous rosettes, anticipating a charming display the next time we have a cool summer.
Flower form survey
The pineapple mountain’s uncommon blossom encouraged me to explore the diversity of flower forms. My research strategy draws upon my usual artificial intelligence tool, ChatGPT, one of a growing number of such tools.
In response to my series of prompts, AI generated lists of flower forms. These included 19 forms of individual flowers and seven forms of clustered flowers (inflorescences). ChatGPT also provided a few examples of each of these forms.
A column with that cascade of information would fill lots of space and try the reader’s patience.
I then prompted ChatGPT to list the major architectural structures of flower blossoms and organize the many forms with those structures.
This column summarizes those structures and suggests how gardeners can work with them.
Architectural structures of flowers
Here are six major architectural categories of flowers.
Radially symmetrical (actinomorphic): Symmetrical all around a central axis; the “classic” round flower form that is easy to hybridize for color and size. Nine flower forms occur in this architectural structure. The double and multi-petaled forms have extra whorls of petals that replace reproductive structures, creating lush, layered flowers. These forms are sought after in hybridized garden plants. Examples: roses (Rosa hybrids, especially floribunda and hybrid tea), camellias (Camellia japonica hybrids), hibiscus (Hibiscus rosa-sinensis hybrids) and peonies (Paeonia lactiflora hybrids).
Bilaterally symmetrical (zygomorphic): Flowers with left-right symmetry; widely hybridized to emphasize dramatic forms and often adapted for bee, bird or specialized pollinators. Four flower forms. Examples: orchids (Cattleya, Phalaenopsis hybrids), snapdragons (Antirrhinum majus cultivars), salvias (Salvia splendens and ornamental hybrids) and fuchsias (Fuchsia × hybrida).
Composite (head/capitulum): Inflorescence composed of many small florets forming one “flower head,” often mimicking a single flower. Breeders emphasize double forms, bright rays and large heads. Four flower forms. Examples: dahlias (Dahlia hybrids, decorative, cactus, pompon types), chrysanthemums (Chrysanthemum × morifolium hybrids), zinnias (Zinnia elegans hybrids) and gerberas (Gerbera jamesonii hybrids).
Spikes and racemes: Elongated axis of an upright stem, bearing multiple flowers, maturing from base to tip and providing vertical drama in garden designs. Seven flower forms. Examples: gladiolus (Gladiolus hybrids), delphiniums (Delphinium elatum hybrids), foxgloves (Digitalis purpurea cultivars) and hollyhocks (Alcea rosea cultivars).
Umbel: Many stalks radiating from one point, like umbrella ribs. Two flower forms: simple and compound. See “Advance your gardening knowledge” below for examples. Examples: onions and related species (Allium), Queen Anne’s lace (Anthriscus sylvestris), carrot (Daucus carota) and fennel (Foeniculum vulgare).
Specialized/trap: Some flowers don’t fit neatly into the five main frameworks: Three flower forms. Some highly modified orchid species have trap/bucket forms, and roses and fuchsias have a floral cup (hypanthium).
Gardening with flower structures
Gardeners can use flower architecture to better understand, appreciate or describe garden blossoms.
A collection of plants within a particular genus could represent a flower architecture collection. For example, a collection of several hybrid cultivars of orchids, salvias or fuchsias can be regarded as a collection of bilaterally symmetrical flowers.
To get deep into this concept, a gardener could develop a collection of different plants within a single category of flower architecture. See the following section for a plan for such a project.
Advance your gardening knowledge
To learn more about flowers within an architecture of interest, gardeners can send a prompt to ChatGPT. More conveniently, gardeners can search Google with a query such as this example: “List flowering plants with umbel structure.”
Enjoy your garden!
Tom Karwin can be reached at gardening@karwin.com.
