Hyacinth Flowers Looser Every Year: What to Do After Flowering

The loosening is normal, not a failure

The first spring after planting, a hyacinth produces the fat, tightly packed truss you see on the packet. The second spring it is noticeably looser. By the fourth or fifth year you have a slender spike with maybe a dozen well-spaced florets that leans gracefully and smells exactly as strong as it ever did. Gardeners regularly conclude they have done something wrong. They have not.

That first dense spike was produced under commercial conditions on a bulb grown for years in ideal field soil, fed hard, lifted, graded and stored at controlled temperatures. No garden reproduces that, and no garden needs to. Once the bulb is living on what your own soil and your own spring give it, it makes a flower proportional to the food it stored last summer, which is a looser one.

Many people prefer the later version. The tight forced truss is a florist's shape and can look stiff in a border; the loose spike sits far better among other spring plants, catches the wind without snapping and does not need staking. It is also the shape the plant makes when it is settled and healthy.

What is not normal is a bulb producing only leaves, or a spike with two or three florets that browns before it opens. That points at planting depth, waterlogging or a bulb that was already damaged, and is worth investigating rather than accepting.

Deadhead the flowers, keep the stem

As soon as the last florets go brown, cut the flower head off. A hyacinth that is allowed to set seed pours energy into seed pods that would otherwise go into next year's flower, and the pods themselves are not attractive. Take just the flowering portion.

Leave the green stem behind. It photosynthesises for several weeks after the flowers are gone, and cutting the whole stalk down to the bulb throws away food the plant is actively making. Cut where the lowest dead floret was, and let the bare stem stand until it yellows with the leaves.

Do this promptly rather than waiting until the border looks untidy. Two weeks of seed pod development is real energy lost, and hyacinths are slower to rebuild than daffodils.

Gloves again for this job if you are cutting more than a few. The sap in the stem carries the same irritant compound as the bulb scales, and a morning of deadheading bare-handed leaves the same itch.

Do not tie, knot, plait or fold the leaves. It is done to daffodils and it damages hyacinths for the same reason it damages daffodils: it cuts the leaf area exposed to light at exactly the point where the bulb is refilling itself.

Feed while the leaves are still green

The six weeks between the flowers fading and the leaves yellowing are when the entire flower for next spring is built and packed into the bulb. Everything you do in that window shows up twelve months later. Everything you do after the leaves die back is too late.

Feed with a high-potassium liquid feed, the sort sold for tomatoes, every ten days or so from the moment you deadhead until the foliage starts to yellow. High nitrogen is the wrong choice here; it produces soft leaves and soft bulbs that are prone to rot. Potassium is what builds flower.

Keep the ground watered through this period if spring is dry. A hyacinth trying to rebuild in dry soil simply builds less. Once the leaves start to yellow, stop watering entirely and let the ground dry out, because the bulb is heading into a dry summer rest and standing water from then on is what kills it.

Let the leaves go all the way to yellow and pull away easily before you remove them. They usually take six to eight weeks after flowering. Cutting them green is the single most reliable way to guarantee a poor spike next spring, and its effect will not be visible until it is too late to fix.

When to lift, split or replace

A hyacinth left in the ground will go on flowering for many years in the looser form. If you want to intervene, the moment is once the foliage has fully died back.

1. Decide whether you need to lift at all In well-drained soil, leave them. Lift only if the ground stays wet through summer, if the clump is congested and flowering has thinned badly, or if you want the space for summer planting.
2. Lift with a fork, wide of the clump Push the fork in six inches (15 cm) outside the leaf marks and lever the whole clump up. Bulbs sit deeper than people remember and a spade through the middle of a group is easy to do.
3. Separate the offsets Small bulbs will have formed against the mother bulb's basal plate. Twist off any that come away cleanly and leave the rest attached. Offsets take two or three years of growing on before they flower.
4. Dry and store cool Clean off loose soil, dry them in an airy shaded place for a week, then keep them in paper bags or open trays at 60 to 65F (16 to 18C) until autumn planting. Never a sealed plastic bag.
5. Replant the biggest, line out the small Full-size bulbs go back into the border at six inches (15 cm) deep. Offsets go into a spare corner at three inches (8 cm) to be grown on until they are big enough to flower.

Track the shape of the spike each year

Note the flowering date, the height of the spike and a one-line description of how dense it was, for each group. Over three years that record shows you a smooth loosening, which is normal, or a sudden collapse in one particular spot, which points at drainage or depth in that spot and nothing else.

Also record the date the leaves finally yellowed and the date you fed. If a group consistently dies back a fortnight earlier than the rest of the garden, it is running out of water or light there, and moving it in autumn is likely to be worth more than any amount of feeding.