Getting it to bloom

Why won't my Greenstem Forsythia bloom? (and how to make it flower)

Also called greenstem forsythia (Forsythia viridissima).

More about greenstem forsythia

About Greenstem Forsythia

Forsythia viridissima · also called greenstem forsythia · flowering

Greenstem forsythia is a deciduous shrub named for its distinctly green, four-angled winter stems. It carries greenish-yellow bell flowers in mid-spring, slightly later than the border hybrids, on bare wood. Stiffer and more upright than Forsythia × intermedia, it is hardy, sun-loving, and easy in any well-drained soil; the dwarf 'Bronxensis' is a popular compact form.

Plant type: flowering

Watch for — Sparse bloom from mistimed pruning: Flowers form on the previous year's stems. Pruning after midsummer removes the buds; always prune within a few weeks of flowering finishing.

The reasons greenstem forsythia isn't blooming

Almost every non-blooming greenstem forsythia traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding greenstem forsythia a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get greenstem forsythia to flower

Maximise sun. Give greenstem forsythia the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for greenstem forsythia and get the feeding right with the greenstem forsythia fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Greenstem Forsythia flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full greenstem forsythia care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Greenstem Forsythia blooming — frequently asked questions

Why won't my greenstem forsythia flower?

Greenstem Forsythia blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make greenstem forsythia bloom?

Give greenstem forsythia the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does greenstem forsythia normally bloom?