Morning Glory

A morning glory is a vine that lives up to its name — the flowers open with the first light, unfurling their trumpet faces to the sun, and by early afternoon they have closed again, wilting into twisted spirals that drop by evening. The show repeats itself every morning from midsummer until frost, and if you are not an early riser, you will miss most of it. The compensation is that the flowers are vivid — electric blue, deep purple, magenta streaked with white — and they appear in such numbers that a well-grown vine looks less like a plant and more like a curtain.

Morning glories grow fast enough that starting them indoors rarely gains you anything. The seeds have hard coats; nicking each one with a file or soaking them overnight in warm water speeds germination, but even untreated seeds sown directly into warm soil tend to catch up within a week or two. Sow one week after your last frost date, when the soil has warmed to at least sixty degrees, and the vines will be shoulder-high by the solstice.

The taproot dislikes transplanting. If you must start indoors, use deep pots and transplant while the seedlings are still small — once the taproot coils around the bottom of a pot, the vine tends to sulk for weeks after being moved. Direct sowing avoids the problem entirely and produces vines that climb more aggressively from the start.

Soil fertility is where most gardeners get morning glories wrong. Rich, heavily composted soil produces enormous vines with lush foliage and very few flowers — the plant puts all its energy into leaves and keeps postponing bloom. Lean soil, on the other hand, stresses the vine just enough to trigger flowering. If your morning glories are all vine and no flowers by late July, the problem is almost certainly too much nitrogen. There is no fix mid-season; plant them in a less-amended spot next year.

Self-seeding is the other caution. In warm climates, morning glories can naturalize aggressively, reappearing year after year from dropped seed and becoming difficult to eradicate once established. Deadheading spent flowers before they form seed pods keeps this in check, but it requires diligence — a vine in full bloom produces dozens of flowers every morning. Some gardeners accept a few volunteers as a fair trade for the spectacle; others find themselves pulling morning glory seedlings out of the lawn for the next five years.

The seeds contain LSA, a compound related to LSD, and are mildly toxic if ingested in quantity. Keep them away from children and pets, and consider this when planting near areas where curious hands or mouths might wander. The flowers themselves are harmless, and the foliage poses no risk to touch.