Mono bouquets in Bangkok: a Thai orchid or a far-off spring flower
Orchids are Thailand's main local cut flower, with almost half the country's orchid-growing area in Nakhon Pathom province and more farms around Bangkok itself, and mono bouquets in Bangkok give the orchid a section of its own among the catalogue's single-variety flowers. The rest of the varieties here are visitors from other climates, so picking one kind comes down to what it says and how long it will last in a vase.
Orchids from Thai farms, tulips and lilac from far-off springs
Orchids are Thailand's main local cut flower. Nakhon Pathom province holds close to half the country's orchid-growing land, and growers also work plots around Samut Sakhon, Ratchaburi and Nonthaburi, as well as sites inside Bangkok itself. That local base is why the orchid has earned a section of its own among the city's mono bouquets.
Tulips, hyacinth, daffodil and ranunculus are a different case: spring bulbs from the northern hemisphere, and lilac only opens in May further north again. Bangkok's year has no season to match either of them; the city runs instead on Bangkok's hot, rainy and cool dry seasons, so these flowers arrive out of step with the climate they come from.
Chrysanthemums, gerberas, alstroemeria, lilies, lisianthus and carnations sit at the other end of the calendar: greenhouse flowers, in the catalogue in any month, which makes them an easy place to start whatever the season outside. Whichever variety you settle on, the florist buys the actual stems only once the order is paid, matching them to the flower chosen rather than holding stock in advance.

A Thai orchid for a friend, or a few heads of hydrangea
In Thai flower tradition, giving someone an orchid signals friendship and support, which makes a single-variety orchid bouquet a natural choice for a friend or a colleague rather than a romantic gesture. A lotus does the opposite job: it belongs to temples and offerings, not to a desk or a doorstep, so it is the wrong flower for this kind of message.
Cut orchids, chrysanthemums, alstroemeria and carnations are the varieties that last, holding for two to three weeks in water, which suits a gift meant to stay around rather than mark one evening. Chrysanthemum leaves yellow before the flowers do, so stripping them off as they turn keeps the stems looking fresher for longer.
Hydrangea works on a different scale: a few heads already read as a full bouquet, since each one does the visual work of several smaller flowers. It drinks more than most cut flowers and takes in water through its petals as well as its stem, so a head that has gone limp can often be revived by lowering it into cool water for an hour or two. One flower worth avoiding in a home with a cat is the lily: every part of it is toxic to cats.
Mono bouquet delivery in Bangkok: a few heads or a dense field
Large-headed flowers such as hydrangea, lily and sunflower fill a bouquet with only a handful of stems, because each head carries the weight of several smaller ones. Small-flowered varieties such as baby's breath and matthiola need closer to twenty stems before they read as a dense field rather than a scatter of blooms; take both figures as a starting point, not a fixed rule.
The exact stem count is worth putting in a message to the florist, who can send a photo and a price before anything is charged. In a single-variety bouquet the shade carries the whole arrangement, so that photo, taken before the courier leaves, is the moment to check it and ask for a change if the tone looks off. If a particular variety is out of stock, the florist substitutes one close in shade and price, and the swap shows up in the same photo rather than arriving as a surprise.
Delivery within the centre is free, and other districts are charged by zone. Each bouquet's own page shows its exact delivery timing rather than a blanket promise, and most orders go out the same day they are placed. The delivery zones page lists the areas and their rates. The card can carry a signature or stay anonymous, whichever the sender prefers.

Choosing a single variety for Bangkok starts with the occasion. Orchids suit a friend or colleague, since a gift of this flower says more than romance. A few heads of hydrangea read as a full bouquet despite the short stem count, while alstroemeria stays fresh for a bouquet that still looks good two weeks on.