This is a very commonly asked question, and also a difficult one for us to answer. The reason it’s so difficult to answer is that everyone’s situation is different. Every single yard and even locations in the same yard are different. Unfortunately, it can be very difficult to remotely determine what is going wrong. This list of 5 common reasons why your passion flower isn’t flowering is an excellent place to start troubleshooting.
Reason 1: Sun exposure
As a general rule, passion flowers are full sun plants. They’ll grow in partial shade, but they won’t flower. Unfortunately, 6-8 hours of sunlight isn’t enough to make them happy. Their preference is to be in a full dawn to dusk sunny location. Some light/dappled afternoon shade can be desirable for some varieties in very hot locations. However, for the majority of the United States, and the majority of passion flowers, getting them as much sun as possible is ideal.
If your passion flower isn’t flowering and its in a shady or semi-shady location, moving it to a more sunny location is the first thing we recommend trying. In our opinion, this probably tops the list for why passion flowers aren’t flowering. This is particularly true of any of the free flowering hybrids.
The reason we say this is that in the early spring a lot of our plants start actively growing and putting out flower buds. As soon as we put a light shade cloth over the greenhouse to help moderate temperature flowering stops. Even the most free-flowering varieties stop flowering. So try this first!
Reason 2: Daylength
Depending on which variety or species you are growing, this can also be a very valid reason why your passion flower isn’t flowering. Some varieties are photoperiod sensitive and will only bloom when the number of hours of daylight is correct. For example, if a passion flower you are growing is a short day variety like Passiflora ‘Maui’, it will not bloom in the middle of the summer no matter what else you do.
This is more likely to be the case for passion flowers in our Rare Passion Flowers category that are species rather than hybrids. Most, but not all of the named hybrids are easier to get to bloom, and they typically bloom over a longer season. If you have a question about what we find the flowering period for a particular plant to be, you’re welcome to ask.
Reason 3: Age/size
Some passion flowers seem to need to attain a sufficient size or maturity before they start flowering. This is again less common with the named hybrids than many of the species. Sometimes after planting a new plant, they will go into a stage of rapid vegetative growth where the plant is focusing on producing leaves and roots rather than blossoms. Later as the conditions become more favorable it may start flowering.
If you are hoping for a passion flower that will jump straight into flowering for you, many of the varieties in our Easy Care category are very free flowering. Varieties such as P. ‘Fata Confetto’, P. ‘Lady Margaret’ P. ‘Clear Sky’ and P. ‘Blue Velvet’ will set buds on tiny little plants, and we often ship them with buds.
Reason 4: Temperature
Temperature can also be a big problem. Both too hot and too cold can cause issues depending on the variety. Some of the very tropical heat loving varieties want it warm to flower. They won’t bloom in cold temperatures, and may never bloom well or at all in some locations. Conversely, many varieties that don’t like heat may abort buds or stop making buds in hot weather.
We try to list on descriptions if a variety is heat loving, or heat intolerant. Some of the worst offenders for not flowering in the summer due to heat are P. ‘Monika Fischer’, P. ‘Lavender Lady’, and pinks like P. ‘Anastasia’. Often these varieties will not bloom in the summer in the deep south, but may really shine in the spring and fall. However, in many of the cooler parts of the country they will bloom happily all season and out -perform heat loving varieties.
Reason 5: Nitrogen
Lastly, we are including too much nitrogen on our list. We are mainly including it so that we can address the mis-information. This seems to come up as the “most common reason” if you do a Google search, and we find that many times people are afraid to fertilize and care for their passion flowers because they’ve been warned that they “need poor soil or they won’t flower”. As a result we get people sending pictures of plants that are obviously desperately starved of nutrients asking what’s wrong.
So yes, it is absolutely true that too much nitrogen can reduce flowering. However in our experience having that level of nitrogen isn’t very common. It is absolutely not true that passion flowers need poor soil or to be nutrient starved to bloom! So while technically a possible reason, in actual practice it seems pretty unlikely to be the reason as compared to the above 4 reason.
Too little fertilizer can actually be equally if not more detrimental to getting your plant to bloom.
Passion flowers only flower on new growth. They set buds in the leaf nodes as they are developing, so if your plant is nutrient starved and not actively growing much, it won’t be setting flower buds.
In our experience passion flowers are heavy feeders. This makes sense since they are growing so rapidly. We recommend treating your passion flower the same as any other flowering plant you are growing. It does need feeding, particularly if you are growing it in a container. We recommend using a fertilizer designed for blooming plants. These fertilizers have lower nitrogen and higher phosphorus and potassium levels.
If you have eliminated all the other reasons on this list and your plant is putting out excessive vegetative growth and not blooming, you can try slowing down the fertilizer. If you haven’t been feeding your plant for fear of it not blooming, try giving it a fertilizer boost. This is particularly important if it looks yellow, the leaves are speckled, or it otherwise looks hungry for nutrients.
Lastly, if you have questions about a specific variety, or have tried everything and still can’t get your plant to bloom, you are welcome to contact us. We can’t guarantee that we will be able to get it flowering for you, but we will do our best to help you troubleshoot the problem.
Next time we are going to be discussing our favorite long blooming perennials. Don’t forget to sign up for our newsletter so that you don’t miss out!
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