Mixed bouquets in London: from a royal cascade to a bunch for today
On 29 July 1981, at St Paul's Cathedral, Diana carried an about metre-long cascade that mixed gardenias, stephanotis, odontoglossum orchids, lily of the valley, Earl Mountbatten roses, freesia, veronica, ivy, myrtle and tradescantia. Mixed bouquets in London still follow the same idea: one flower sits at the centre and carries the weight, smaller blooms and greenery fill in around it, only with far fewer stems.
Roses at the centre, lisianthus around: what goes into a London mix
A London mix usually settles on one flower to build around. The arrangement sold as Roses with Lisianthus does this in the plainest way: a rose holds the middle, ruffled lisianthus loosens the shape around it. Elsewhere in the same style the centre moves to lilies paired with gerberas, to a single hydrangea head, or to chamomile daisies scattered through greener stems, and a few bunches lean into lavender tones instead of picking out one bloom at all. That pattern runs through most mixed bouquets in London, whatever the combination on any given day.
Roses do this job well because each stem carries one flower, which gives a bouquet an obvious centre and enough weight to hold the rest together. They can anchor a London mix in every month of the year largely because about nine tenths of cut flowers sold in Britain are imported, and Kenya, one of the main suppliers, sends little besides roses.

Lilac in May, daffodils in spring: seasonal stems in a London mix
Lilac has one month in a London mix, May, when it is cut at home rather than flown in from further south. British growers cut peonies from late April into June, though anyone who wants the flower on its own, not folded into a mix, is better served by a full peony bouquet from its own section.
Daffodils run on a stricter calendar and a stricter rule. Cornwall cuts them from January to April, and a freshly cut daffodil stem weeps a sap that clogs whatever other stems share its water. A florist stands them in their own water for a day before adding them to a mix, then leaves the stems uncut once they go in; cutting them again at that point only releases more sap into the vase. Mothering Sunday is the other date that pulls the demand for spring mixes up sharply each year.

Stems that last two weeks, and a chrysanthemum without gloom
A mixed bouquet's life is set by its shortest-lived flower, not by the arrangement as a whole. Chrysanthemums, carnations and alstroemeria last two to three weeks in water, while a rose manages about one. Put a rose next to a chrysanthemum and the bouquet is only ever as fresh as the rose allows.
The Bouquet of Long-Lasting Tender Flowers is named without listing its stems; what goes into it is visible in the photograph taken before the courier leaves.
Chrysanthemums carry no funeral association in Britain and turn up in everyday bouquets without anyone reading anything into them. The flower is read differently in France, Italy and Poland, so a large chrysanthemum head is worth swapping for something else if the recipient grew up there. Its leaves also yellow well before the bloom fades, and a florist strips them off the stem rather than leave them on. Central heating speeds that fade along further, a point our guide to flowers in London goes into in more detail.
Every mixed bouquet is put together once the order is paid, not kept ready-made on a shelf, and a photo goes to the sender before the courier sets off. Where one stem is out of stock, the florist substitutes a flower close to it in colour and price, and that change is visible in the photo rather than left unmentioned. Mixed bouquet delivery in London is free within the centre and charged at a fixed rate for the recipient's zone elsewhere, with the zones set out on the delivery page; the time itself appears on each bouquet's own page rather than in general terms here.
Anyone who wants one flower rather than a mix has two narrower places to look: mono bouquets built around a single kind, and roses on their own, the flower that already sits at the centre of most mixes in this range. For something more worked than a hand-tied bunch, designer bouquets take the arrangement a step further.