One of the things we are most frequently asked is “what passion flower would be best?”. So today we are going to look at how to select an appropriate passion flower. “Best” is always going to be subjective to your specific wants and needs, but this is how to evaluate what we have vs what you’re looking for.
Firstly, you need to define what you want your plant to do for you.
Are you planning to plant it in a pot and overwinter it inside? Do you want it to be cold hardy in the ground? Do you want it to cover a fence? Should it be small and manageable? Are you looking for fruit or would you rather it be sterile? And the list goes on. So what is it you want from your plant?
Once you have considered what you want out of your plant, then you need to consider what you can practically provide for it. What we mean here is what kind of conditions do you have to keep your plant in. We are talking about answers to things like the following questions. Are your summers cool or blazing hot? Can you provide it with full sun? Are you overwintering it as a house plant, or does it need to go dormant so you can store it in a garage? Are you new to growing passion flowers or do you have experience? Can you keep it in a 10 gallon pot or only a 3 gallon one?
Once you are armed with this kind of information we can help you to make an educated guess about what would work best for you. Keep in mind that every location and every grower is different, there are a million different variables and micro climates that can affect your plant’s growth. So, you still might have to do some experimenting to find the absolutely best variety.
Passion flowers are an incredibly diverse number of species from an amazing array of different environments ranging from blazing hot to cool and temperate.
As thus, not all passion flowers perform equally. We have tried to break our varieties down into a few categories to make selection easier. The plants in our Easy Care category are typically going to give you the most bang for your buck in terms of flowering and ease of care. Most hybrids are going to out perform straight species. The named hybrids have been specifically selected for their garden performance.
However, one thing is still a non-negotiable essential for all passion flowers. Passion flowers are full sun plants. Most of them are not going to bloom with 6-8 hours of sun. Unless they need protection from heat, they will perform best with full dawn to dusk sun. 8 hours is an absolute minimum. Though many passion flowers will grow well in the shade, they will not flower.
If you are looking for something unique, you can grab something out of our Rare Varieties category.
Keep in mind thought that these varieties typically are much more fussy to grow and many of them only bloom for a short time. Their blooms can be spectacular though if you can coax them into flowering. P. miersii and P. sidifolia are good examples.
If you are looking for a fruiting variety in much of the country, Passiflora incarnata is unfortunately your only real choice. While there are many varieties that grow fruit they are really only suited for warm places like California or Florida. P. edulis is the most commonly grown variety for fruit. Even container grown P. edulis does not have a long or warm enough season to produce fruit in most places.
If you are on the eastern half of the country, Passiflora incarnata and its hybrids are some of the best choices. This is because Passiflora incarnata is native here. It is well adapted to the growing conditions. In terms of size, vigor, number of flowers, ease of care and overwintering ability they are hard to beat. They shrug off heat and humidity often seen in the summers here. They are pollinator magnets that will bloom steadily all summer long.
If you are in the deep south, you need to look for varieties that love heat.
We have many of them including most of our P. incarnata hybrids and the P. caerulea hybrids, but also less common ones like P. holosericea. Typically, most pinks do not do well in heat and humidity, and with the possible exception of P. Victoria, they should be avoided. They are not a good choice for a hot humid location unless you are prepared to baby a plant and possibly lose it to heat stress.
Many of the less heat tolerant plants will survive but will drop flower buds in high temperatures. This is typically listed in the descriptions. These plants should be avoided unless you are ok with only having flowers in the cooler weather. Examples of plants that will live but drop buds/stop flowering in high heat include P. Monika Fischer and P. Lavender Lady, and P. loefgrenii x caerulea. Though P. Lavender Lady really shines in the fall in hot climates when not much else is in bloom.
If you live in a colder part of the country, it is essential to choose a variety that is both cool weather tolerant and also free flowering.
Many of the less free flowering varieties will not bloom well in the north. This is either due to it not being warm enough, not being warm enough for long enough, or warm enough when the number of hours of daylight is sufficient to trigger blooming. Typically you would want to stick with cold hardy varieties, or anything that mentions that it prefers cool weather. P. Belotii is particularly well suited to growing in cooler climates as it overwinters easily as a house plant. This was our passion flower of choice when living in Vermont. Varieties like P. Fata Confetto and P. Blue Velvet and P. Lady Margaret can also be good choices.
If you’re lucky enough to live in a moderate, frost free environment like California, you can grow almost anything successfully so long as you water them sufficiently. This is also the sort of place where winter blooming reds like P. Maui really shine. Winter blooming plants are a disappointment in most areas.
If you live in the sort of middle part of the country where summers are fairly warm and long, you can grow a wide variety of passion flowers.
Most of the heat intolerant ones will do ok, and it is also warm enough to grow many of the heat loving varieties. You just have to grow many of them as disposable annuals or in containers that you can bring inside to overwinter. Nonetheless, their spectacular blooms can be worth it!
If you are wishing for a passion flower to overwinter outside in much of the United States, your choices are fairly limited. P. incarnata is the most hardy variety we grow, and many of its hybrids come in second. Check out our Cold Hardy category and compare the listed hardiness zone to yours.
When discussing cold hardiness in passion flowers, it is essential to note that your location MUST be dry.
Passion flowers are very susceptible to root rot and wilts particularly in cool temperatures. If your plant is in a location that it sits wet over the winter, it will die regardless of the temperature. Keep in mind that passion flowers can be unreliably hardy, particularly in marginal soil conditions in climates close to their limit. Planting your plant in a warm sheltered microclimate that is very well drained and mulching it thoroughly can help it to survive winters better.
If you are looking for a plant that goes dormant and can be overwintered in a cool location like a garage or basement, P. incarnata’s hybrids, and P. Blue Bouquet or P. Lavender Lady all go dormant and overwinter well. P. caerulea hybrids can also go dormant though we find that they prefer to go semi-dormant and be kept somewhere that they get light.
Lastly, if you live in the Pacific Northwest, P. caerulea types will probably perform better than P. incarnata types. While we do not have personal experience growing passion flowers there, it is our understanding that P. caerulea tolerates the cool damp conditions there better than P. incarnata which is adapted to the heat and humidity of the southeast. It can be different to overwinter in the northwest due to the wet climate.
Hopefully this clarifies some differences between different groups of passion flowers and makes selecting your next plant easier! Next time we are going to discuss reasons why your passion flower isn’t blooming. If you’re interested in reading about that, please sign up for our newsletter to have it delivered to your inbox!
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