Mono bouquets in San Francisco: dahlias, chrysanthemums and the right shade
The dahlia has been San Francisco's official flower since 1926, and Dahlia Dell in Golden Gate Park peaks in late August and September. Among mono bouquets in San Francisco the dahlia keeps its own section, and picking one variety here comes down to the season and who the bunch is for.
Dahlias and chrysanthemums for a San Francisco autumn
Dahlia Dell sits in Golden Gate Park beside the Conservatory of Flowers. The Dahlia Society of California keeps its beds blooming from June, peaking in late August and September and running into October. In the northern hemisphere both the dahlia and the chrysanthemum belong to late summer and autumn, which is why a single-variety dahlia bunch reads best as an autumn order rather than a spring one.
The dahlia's section among mono bouquets in San Francisco stays small. If a particular shade is out, the florist substitutes a close colour at a similar price, and the swap shows up in the photo sent before the courier leaves, so nothing arrives as a surprise.
Chrysanthemums work differently. They're greenhouse flowers, cut all year round, so a spray chrysanthemum bunch isn't tied to any one season the way a dahlia is. In the vase it lasts two to three weeks, though the leaves usually turn before the flower does and are worth stripping off as they go. San Francisco's September tends to run warmer than its summer, a quirk covered in the city's flower guide.

Yellow and white: two shades a Chinatown family leaves out
In the United States a chrysanthemum usually reads as a cheerful, everyday flower. In China the same bloom stands for longevity, and that difference travels with the people who keep the older tradition.
Chinatown and many Chinese-American families hold to a rule from that tradition: white flowers and yellow chrysanthemums belong to mourning, not to gifts, and the rule matters most in the stretch around Lunar New Year.
The practical result for a bouquet meant for such a household is straightforward: choose a chrysanthemum in another colour. White lilies, calla lilies and a cloud of baby's breath fall under the same rule and are best left out of that gift too. Shades can read differently on a screen than in hand, so the exact colour is easiest to check in the photo the florist sends before the courier leaves.
One variety for a weekday desk, another for a home with a cat
San Francisco's Financial District fills up on weekdays and empties out by evening and at weekends, so a bouquet meant for a desk is best sent on a weekday, during office hours.
For a surface that won't be refilled for a while, the longer-lasting single varieties do more work. Alstroemeria, dianthus — the carnation's own section — and a cut orchid all hold for two to three weeks in water, well past most other mono bouquets in the catalogue.
A home with a cat rules lilies out entirely. Every part of the lily is toxic to cats, pollen and the water left in the vase included, so a cat owner is better served by a different single flower altogether rather than a lily kept carefully out of reach.
Mono bouquet delivery in San Francisco is free in the centre. Elsewhere a flat zone fee is added before payment, and the delivery time itself is shown on the bouquet's own card; the zones and fees are set out in the delivery terms.

A first mono bouquet in San Francisco is easiest to pick by season and by address. Dahlias make sense within their short late-summer-into-autumn window, while a chrysanthemum works in any month, provided its colour suits the household it's going to. For a home without a cat, lilies stay on the list; for one with a cat, they come off it.