For my own Valentine, who is gimpy after hurtling himself and his bike over the hood of a car and breaking his foot last Wednesday, I took what little material I had available to me on my plant shelf and created a simple centerpiece for our coffee/dining-room-in-the-living-room table, where we had our romantic take-out dinner of vegetarian General Tso's "Chicken" and steamed vegetable dumplings while watching some of the final episodes of Battlestar Galactica.
It's in a wine glass with a tad of water. The bulk of the arrangement are cuttings of Plectranthus 'Mona Lavendar,' with its cheerful splay of striking flower spikes above the riot of dark green and purple leaves. Interspersed among Mona's foliage are zig-zaggy branches of Pedilanthus tithymaloides (or for-really Euphorbia tithymaloides, according to the The Plant List search I just did) with nice green mid-leaf regions accented by a light, limey-green colour that contrasts well with the lavender of Mona's flowers and dark purple of the bottom of her leaves. Primulina tamiana flowers tie everything together, hidden at the bottom (it would have been nicer to have a few stalks of these in the arrangement, but I had limited inflorescences, and I wanted to leave most of them on to produce more seedpods).