An almost forgotten scented plant ideal for a greenhouse is Mignonette. Allegedly a ’discovery’ of Napoleon, who sent seed to Empress Josephine from his Egyptian campaign in 1798 (Reseda odorata grows wild in N. Africa). Her followers adopted Mignonette (French for ‘little darling’) which soon became fashionable, especially in pots for perfuming balconies and terraces. Apparently first grown in UK in 1752 by Philip Miller at Chelsea Botanic Garden, who had been sent the seed by Dr van Royer of Leiden…
We have native two Reseda species in the UK, there are sixty or so worldwide, all annual but only the one, R. odorata, is fragrant. And what a lovely scent, just fills your greenhouse. But seldom overpowering, strongest in the warmth of an afternoon and not an evening-only scent you have to come back for.
Admittedly the plant itself is not exactly eye catching, indeed a rather straggly ‘weed’. The gorgeously scented flower spikes are nice enough, not that showy though long lasting, with bell shaped seed pods after. Selection has improved Mignonette somewhat, though beware, larger brighter flowered forms have lost some of their perfume, which was really the whole point. Just grow the original in pots hidden amongst more showy companions.
Mignonette is an annual so best sown individually in small cells and potted on regularly so it receives no check. It will bloom in small pots but be stunted. Pots 5-6”/12-15cm just sufficient, larger are better. Now if you are very keen it’s possible to have some flowering almost every day of the year, one reason it was so popular. However this requires sowing in at least three or more batches, February, July and August and nipping out flowering shoots till required.
Another interesting, well challenging, technique was to train the best shoot up a short cane (a foot or so/30-50cm) and carefully nip out side shoots to form a tapered conical Christmas tree shape which would bloom all over with flowery candles. (I’ve tried this, fiddly, could have done better, much better, try it and send me photos.)
Machet is the traditional variety, others seldom seen or sadly lost: Golden Goliath, Orange Queen, Crimson Giant, Triumph.