Ammi majus is one of an extremely short list of plants that could be described as almost too good to be true.
‘Typical McCoy hyperbole’ you think? Here’s the justification for such a would statement, in bullet points
- It’s a great team player – pretty in the extreme but not overly showy, making great visual partnerships with the flowers and foliage of virtually all surrounding planting
- It has fabulous form in bud, flower and seed
- Once you’ve introduced it, via young plants or via seed, it’ll likely self-sow
- It can be sown in autumn for spring flowering, and/or spring for summer flowering, and/or (if you have water for irrigation) summer for autumn flowering
- Its flower to foliage ratio is very favourable, with the flowers sitting high above the foliage – a great benefit when you’re growing it as a supporting act ie to make surrounding flowers look better
- It’s remarkably drought tolerant
- You can, to some extent, control its ultimate height by cutting out the central leader once the plant approaches the desired height.
But, of course, it’s not perfect. Again, in bullet points
- It can self-sow a little too enthusiastically, particularly in autumn, so that you’re forced to thin the seedlings out. Not doing so can end up with tall, thin plants that don’t flower for long, shade out everything in the vicinity, and fall over, in one great leaning crowd, during flowering time
- It can go down to disease during flowering time – particularly if stressed (which mine usually are, with no water to give them). This is accompanied by a silvering of the leaf, and wilting, both of which point to some sort of sucking insect being the culprit, though I can’t way I’ve seen any with the naked eye.
So it’s very clear that the pros far outweighs the cons.
Autumn sown/winter grown plants will build up much greater bulk and strength than those sown at other times. My winter-grown plants will often flower in November/December at 2m. Spring sown, summer grown plants will flower in late summer/early autumn at about half this height. As much as I love the height of winter-grown plants, I find that they’re often entirely out of proportion with the surrounding plants, to the extent that there’s no visual connection between them. It’s also highly recommended to stake the super-tall plants, as they’re very often top-heavy. In order to minimise both of these challenges I often take the central ‘leader’ out of each of the plants at about 1m high. This minimises the need for staking and brings the flowers down to a height more companionable with the relatively shorter flowering of late spring/early summer flowering perennials.
Unless, of course, I’ve planted them with white foxgloves. In that case, I stake, then let rip.
In what season does Ammi majus work best for you, and what kind of intervention (eg staking? height control?) do you find that it requires?