Planting Balloon Flower: Choosing a Spot You Will Not Change and Setting the Taproot Right

Choose the position as if it were permanent, because it is

A balloon flower sends a thick fleshy taproot straight down and holds most of its reserves in it. That root does not transplant well once it is established, and a plant moved in its third or fourth year usually sulks for a season and often never regains its full size. So spend the time on the decision now rather than expecting to adjust it later, and assume that where you put it is where it will live for a decade.

Give it sun. Full sun produces short, sturdy, self-supporting stems and the heaviest crop of buds; light afternoon shade is acceptable and even helpful where summers are severe; anything less than four to six hours of direct light gives you a tall, leaning plant with few flowers. Look up as well as around before you commit, because a young shrub or tree that is fine today will be casting shade over the spot in five years, and the balloon flower cannot be moved out from under it easily.

Then think about the neighbors, because of the late emergence. Put it beside plants that do not need annual lifting, dividing or replanting, and avoid interplanting it with anything that gets dug over each year. A good companion is something that comes up early and covers the bare patch politely while the balloon flower is still below ground: a low, shallow-rooted plant that does not compete at depth is ideal, since the taproot is working well below the level where such a neighbor feeds.

Building the ground: depth matters more than richness

The usual instinct with a perennial is to enrich the planting hole. Resist it here. Balloon flower grows perfectly well in average and even poor soil, and the richer the ground the taller and softer the stems get. What it actually needs is depth and drainage: loose, open soil that a taproot can drive down through, and no water standing in it during the cold months.

So loosen deeply over a reasonable area rather than digging a narrow pit and filling it with compost. Fork the ground to at least ten inches (25 cm), further if you can manage it, breaking up any compacted layer you meet. On heavy clay, work a third by volume of coarse grit through that depth and plan to set the crown on a slight rise so surface water sheds away from it. On sandy ground, a moderate amount of leaf mold or well-rotted compost mixed through will hold enough moisture for the first season without making the soil rich.

Test the drainage before you commit. Dig a hole a foot (30 cm) deep and fill it with water. Draining within a couple of hours is fine. Water still standing the next morning means you should not plant a balloon flower there: build the bed up, or use a raised bed or a deep container instead. This is the one condition the plant will not forgive.

Putting the plant in without breaking the root

Handle the root ball as little as you possibly can. Where most perennials benefit from having a congested root ball teased out, a balloon flower does not: teasing out means snapping the taproot's side roots and often the tip of the taproot itself. Slide it out of the pot intact, keep it intact, and get it into the ground quickly. Plant in spring, once the shoots are showing and the soil has warmed above about 54F (12C), so the plant has the whole season to establish.

1. Water the plant in its pot first Soak it thoroughly half an hour before planting. A dry root ball crumbles as you handle it, which is exactly the damage you are trying to avoid, and it repels water for weeks afterwards.
2. Dig deeper than the pot, and no wider than necessary Make the hole a little deeper than the root ball on loosened ground, then firm some soil back into the base so the crown will finish level with the surface.
3. Slide the plant out without disturbing the roots Support the crown with your fingers, invert the pot and let the root ball slide out whole. Do not tease, tug, cut or loosen the roots in any way.
4. Set the crown level with the soil surface The point where the shoots leave the root must sit exactly at the finished surface. Buried, it rots in the first wet spell; proud of the surface, it dries out.
5. Backfill and firm gently with your hands Work soil in around the root ball with your fingers and firm with the flat of your hand rather than treading, which compacts the ground the taproot has to grow into.
6. Water in slowly and thoroughly Soak the whole planting area to close air pockets around the roots. Then let the surface dry between waterings rather than keeping the ground constantly wet.
7. Mulch in a ring and mark the crown Spread mulch around the plant but leave a couple of inches (5 cm) of clear ground at the center. Push in a labeled marker before you walk away.

Containers, and moving a plant you have to move

Balloon flower grows well in a pot provided the pot is deep. Choose depth over width: a tall container of at least twelve inches (30 cm) suits the taproot far better than a wide shallow bowl of the same volume. Use a loam-based compost with about a quarter coarse grit added, keep the drainage holes genuinely open, and stand the pot up on feet so water runs straight out. Container plants dry faster than open ground, so check them properly through hot weather, but never let the compost stay saturated.

Repot only when the plant is clearly outgrowing the container, in spring as growth begins, and move it up one size with the root ball kept whole. Do not shake the compost off, do not divide it while you are at it, and do not cut the taproot to fit a pot you preferred the look of. If the root has curled around the base of the old pot, the honest fix is a deeper container, not a shorter root.

If you genuinely must move an established plant in the ground, do it in early spring as the shoots first appear, dig far wider and much deeper than feels necessary, and go down to get under the whole taproot rather than levering the plant up. Expect a season of reduced flowering afterwards even if you do everything right. In many cases the better answer is to leave the parent where it is and raise replacements from seed for the new position instead.

Nursery plants are often sold dormant, so a pot that looks like bare compost in spring may be perfectly healthy. Check for a firm, fleshy root just below the surface rather than assuming the plant is dead and discarding it.

The first season, and what to record

Water a new plant thoroughly whenever the top two inches (5 cm) of soil dry out through its first summer, soaking the area slowly rather than sprinkling daily. It is building the root that will make it independent later. Do not feed it beyond a thin ring of compost, do not pinch it hard in the first year unless it is obviously drawing up soft, and do not expect a full display; a young plant, especially a seed-raised one, often gives leaves in year one and flowers properly in year two.

Record the planting date, the exact position measured from something permanent, the result of your drainage test, and how quickly water cleared from the ground after the first heavy rain. Add the date the shoots first appeared, since it will be later than you expect and knowing your own garden's normal date saves a great deal of unnecessary worry. Note the finished height and whether the stems needed support, because that is what tells you whether to pinch next season.