Spring is the changeover people most want to rush, and rushing it is the most expensive mistake in the container year. A hard night in late March will take out an entire porch of tender annuals, and it happens often enough that we plan around it.

Wait for mid-April

Greenville’s average last frost falls at the end of March (NOAA’s 1991 to 2020 records put the even-odds date for a 32°F night at March 28). In the higher parts of the county (north of Travelers Rest toward the mountains, where the zone drops to 7b) it is a week or two later than that.

Average means average. A freezing night still turns up after April 1 in roughly four years out of ten, and the odds do not drop to one in ten until around April 12. Frost can also settle on leaves when the air is a few degrees above freezing, so we wait for mid-April before tender annuals go in. If you cannot resist planting in March, keep an old sheet by the door. Covering a container the night before a late frost genuinely works, and it takes two minutes.

What you can do in March is the tidying: pull the winter pansies once they start to stretch, cut back anything woody that carried through, and refresh the top few inches of soil. That buys you a clean start without risking anything.

What comes out

Pansies and violas are the usual winter occupants, and they will tell you when they are done. As the days lengthen they stretch, go leggy, and flower less. They are finished once real heat arrives, usually in May, so there is no reason to be sentimental about them.

Cypress and evergreen structure from the holiday planting can often stay. If a lemon cypress came through winter looking well, it will carry straight on into spring and summer: one less thing to buy, and it keeps the vertical line while everything around it changes.

What goes in

Spring here is mild and short. We go from frost risk to genuine heat in about eight weeks, which means anything you plant needs to establish quickly and then survive a June that arrives early.

Choose for May and June, not for April. A plant that looks perfect in cool April light and then collapses the first week it hits 90°F has cost you the season.

What works:

Snapdragons and dianthus handle the cool start and keep going into early summer
Petunias and calibrachoa for trailing color: reliable and they take our humidity
Geraniums for structure; give them a few hours of midday shade once real heat arrives
Herbs: rosemary, thyme and basil all do well in Upstate containers, and an herb planter by a kitchen door earns its place four ways
Ferns for shaded porches, where flowering annuals will only sulk

If you want bulbs in spring, they have to go in the previous autumn. Every year someone asks in March, and the honest answer is that the window closed months ago: bulbs go in from October into early winter here.

Plant it looking sparse

This is the mistake almost everyone makes, and it is worth stating plainly.

A spring container that looks full and finished the day you plant it will be crowded and airless by June. Spring plants in the Upstate grow more than people expect, because they get a long warm run at it, and crowding cuts airflow, which in our humidity is how you get rot in the middle of an otherwise healthy arrangement.

It should look slightly bare for about two weeks. That is correct. It will fill in.

Watering changes fast

A spring container needs far less water than the same container in July: perhaps twice a week rather than twice a day. But the shift is not gradual: it happens over a couple of weeks in late May.

The habit worth building now is checking rather than scheduling. Push a finger two inches in. If it is damp, leave it. If you build that habit in April, you will not kill anything in June.

What comes next

Spring planting carries through until the heat properly settles in. The summer changeover is less about swapping everything out than about replacing whatever did not survive the transition and shifting toward plants chosen for August.