Getting it to bloom
Why won't my Compass Plant bloom? (and how to make it flower)
Also called Compass plant, Pilot weed, Rosinweed compass plant (Silphium laciniatum).
More about compass plant
About Compass Plant
Silphium laciniatum · also called Compass plant, Pilot weed · flowering
Silphium laciniatum is a dramatic, deep-rooted native prairie perennial of the central and eastern US, famous for its deeply pinnately-lobed basal leaves that orient north–south along a compass axis (reducing midday sun exposure), and for towering spikes of yellow daisy flowers in midsummer. The plant develops a massive taproot that can reach 4.5 m (15 ft) deep, making it extremely drought-resistant but also meaning it strongly resents transplanting once established. The most critical care fact is to site it carefully in its permanent position before planting, as moving an established plant almost always kills it. Silphium is not listed on the ASPCA toxic plant database and is not considered toxic to pets.
Plant type: flowering
Watch for — Slow establishment: Focuses energy on root development for the first 2-3 years and may not flower until year 3-5; patience is essential. Do not mistake slow above-ground growth for failure — check that the root crown is still viable.
The reasons compass plant isn't blooming
Almost every non-blooming compass plant 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 compass plant 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 compass plant to flower
- Maximise sun. Give compass plant 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 compass plant and get the feeding right with the compass plant 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
Compass Plant 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 compass plant care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.
Compass Plant blooming — frequently asked questions
Why won't my compass plant flower?
Compass Plant 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 compass plant bloom?
Give compass plant 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 compass plant normally bloom?
Compass Plant flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.
What should I do with compass plant after it flowers?
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.
What is the single biggest mistake stopping compass plant flowering?
Feeding compass plant a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.
Keep reading
- Compass Plant care — the full brief (light, water, humidity, problems, pet safety)
- Compass Plant light needs — usually the first thing to fix for flowers
- Compass Plant fertilising — the right feed for buds, not just leaves
- Should I water my plant? The simple check
- Why is my plant wilting? Wet vs dry
- Underwatered plant — signs and rehydration
- Why won't my peace lily bloom?
- Why won't my jade plant bloom?
- Why won't my tomato bloom?
- All 4114 bloom guides in the Growli library