Philodendron propagation can also be achieved through vegetative methods, such as stem cuttings, which have been the most common means of propagation for many years. With the advancement of tissue culture techniques, new plants can also be grown from meristematic tissue. However, these methods most often result in plants that are genetically identical to the parent plant, limiting the diversity in the population. In contrast, seed propagation through breeding allows for the creation of entirely new genetic combinations, resulting in a wider variety of plants with unique characteristics.
Breeding two species together results in an F1 primary hybrid, which often exhibits extra vigor and hardiness due to nature's way of selecting the best genes from each parent. In theory, F2 hybrids, the second generation of F1, tend to be more variable than F1 hybrids, demonstrating a wider range of genetic mixing. When a hybrid has more than two parents, it is referred to as a complex hybrid. Complex hybrids can produce hundreds of different phenotypes, making the breeding process even more exciting for breeders, as the chances of discovering something unique and special increase with the number of parents in the hybrid.
Philodendron wendlandii inflorescence
Philodendron wendlandii infructescence | Photo @tropicgardenrevelations
Philodendron verrucosum inflorescence exposed showing the bottom female flower 'chamber', sterile zone separating the male flowers at the top of the spadix
After the inflorescence of a philodendron emerges, it can remain unchanged for a prolonged period (Sometimes up to three months!). Then eventually the spathe will open, and typically stay open for around 25-40 hours before closing again. The timing of the flower opening is highly unpredictable and can vary between species (and within clones of the same plant!) with some opening in the afternoon, others in the morning, and some not until after dark. However, most species tend to close their flowers at a similar time, usually between 9-11pm.
Philodendrons exhibit varying patterns of flowering throughout the year, with some species blooming constantly all year for us at maturity, such as P. mamei, while others, like P. gloriosum, may only flower once a year. Environmental factors, such as changes in humidity, daylight length, day-night temperatures, and dry-wet cycles, likely influence their blooming patterns. Species found around the equator may have two flowering seasons as these regions typically experience two dry and two wet seasons. In contrast, regions further away from the equator, in the northern or southern hemispheres, usually only have one dry and one wet season.
A very small amount of Philodendron mamei pollen under microscope
A very small amount of Philodendron mamei pollen under microscope
It is advantageous to be monitoring all flowering plants every day in the late afternoon or early evening, doing one round to observe all inflorescences. An open spathe should be noticeably loose before it will open. Once an open spathe is found, the top half that covers the male parts can be removed (ripped off), and the entire inflorescence is covered with a plastic bag to protect it from the rain. This way, even if pollen collection is delayed the following night, it can still be collected without the inflorescence closing. The plastic bag also prevents rain from washing the pollen into the bottom chamber, which could result in self-pollination, an unlikely occurrence in nature to a fully spathed plant. It is better to eliminate any doubts that the hybridization was successful and not self-pollinated.
After successful pollination, the female parts of the inflorescence will grow and develop into a fruit, known as an infructescence. These fruits typically start to swell within a week or two of pollination, although it may not be noticeable until you peel back some layers on the spathe. It is best to keep some spathe on the plant, as this will help you know when the fruit is ready to be harvested. When fully ripe, the spathe will split and curl back, revealing the fruit. The fruit should be soft and typically has a strong smell. It is important to note that animals such as rats may take these fruits, so if they are precious and low to the ground, it could be worth putting up a small cage to protect them.
The impatient breeder can peel back spathe to see if the fruit is developing
An 'exploded' spathe shows fruit is ready
After cleaning, Philodendron seeds will germinate under moist conditions. Light may speed up the germination process and could even be essential for germination, but further research is needed to confirm this. We have found that drying out seeds for ease of planting is fine, but drying them out for storage purposes does not work. In our experience, seeds dried for storage purposes and planted one month later had 0% germination.
For more information on Philodendron seeds and our experience growing them, please refer to our guides Growing Philodendron from Seed (coming soon) and How to Clean Philodendron Seeds (coming soon).
Philodendron cv. Florida inflorescence
Philodendron gloriosum fruit containing thousands of seeds
Philodendron pollen unique that it only makes pollen in a section in all observations of prevalent clone in Australia
Philodendron mamei flowering at our nursery all year once it gets mature enough
Inflorescence of Philodendron cv. Majestic
Philodendron cv. Majestic 20 days after pollination
Philodendron cv. Majestic 40 days after pollination
Spathe can be peeled right back to mae access to female flowers easy, just leaves some of it so that it can tell you when the fruit is ripe
Philodendron sharoniae pollen collected until the next morning. This will not last as long.
Some species hold onto their inflorescence this was pollinated several weeks before but there is no development when peeling back the spathe
Philodendron melanochrysum inflorescence
Philodendron gloriosum inflorescence
Philodendon Pollination
A Complete Guide to Pollinating your Philodendron Plants to Create New Hybrids and Cultivars
Philodendron breeding has been an underexplored area in the horticultural world, with only a select few dedicated individuals delving into it. This can be attributed to the unique flowering habits of the genus and a general lack of information and interest. However, with the recent surge in popularity of Philodendron plants and the vast networking and information resources available in modern times, there is hope that the field of philodendron breeding will become more widely practiced.
Producing Philodendron seed is a unique propagation method that involves creating an entirely new plant, offering the possibility of a different appearance in each seed, particularly in complex hybrids. Even when a species is self-pollinated, the resulting seedlings generate genetically distinct plants, each with different adaptations to climate, pests, and disease. In addition, these plants could display a random mutation in their form or some form of variegation.
Hybridizers McColly and Miller (Bamboo Nursery, Orlando, Florida) have demonstrated how breeding programs can select and enhance traits in philodendron hybrids through generational breeding. Even species with little to no color on their leaf lamina have been transformed into vibrant, colorful hybrids such as 'Prince of Orange' and 'Black Cardinal’.
Philodendron gloriosum inflorescence
Philodendrons belong to the Araceae family (also known as Aroids). Taxonomically, this family is divided into two groups: those with bisexual flowers and those with separate male and female flowers (unisexual). Philodendrons have separate male and female flowers on their inflorescence, which is a later adaptation in the Araceae family that is also shared with other genera such as Homalomena, Caladiums, Colocasia, and Alocasia. This suggests that these genera share a common ancestor. The female flowers are found in the bottom chamber of the spadix, while the male flowers are located at the top. There is typically a small sterile zone between the two types of flowers.
The inflorescence of philodendron emerges from a bud located at the base of the petiole near the stem axis. It can be singular or consist of up to ten in a recorded species. When multiple inflorescences emerge, they have a type of cataphyll to keep them moist during development.
Philodendron gloriosum pollen
The blooming of the inflorescence is best thought of as a two-night event. On the first night, it is receptive, and on the second night, it focuses on producing pollen. Some species can even self-pollinate while still receptive, though this is unlikely to occur in nature. Many philodendron species emit a unique waxy fragrance and heat up at night to attract pollinators. Pollen is best applied to the receptive flowers after dark, between 8-10pm, but success can also be achieved earlier or even the next morning, with pollination possible but unlikely all the way up to past when the male flowers are making pollen. On the second night, just before the inflorescence closes, it produces pollen, usually around 8-10pm. However, some species, such as P. verrucosum, produce pollen in the early hours of the morning, requiring collection the next day or staying up late.
Philodendron cv "Florida" Pollen
Collecting fresh pollen is ideal, as its viability decreases the longer it is exposed to ambient conditions. Although storage of Philodendron pollen is not well-researched, some success has been reported with frozen pollen remaining viable for weeks in the freezer. For instance, @wildaboutplants have used pollen that was frozen for 4-6 weeks with success. However, we have only ever successfully used fresh pollen that was either collected on the same night or stored in the fridge for 1-4 days. The effect of resin, which is often collected with the pollen and turns it into a paste, on pollen storage is unknown. It is possible that very dry pollen without any resin may be stored in the freezer for an extended period. To dry out collected pollen, it can be left open in the fridge before sealing it in a container and placing it in the freezer.
Philodendron mamei pollen ready for storage
Philodendron species are more likely to cross if they are closely related, and phylogenetic studies are the best way to understand their relationships. However, in Philodendron, distantly related species have on occasion successfully hybridized, while closely related ones have failed for us numerous times, so it is always worth trying. In general, only about 25% of our attempts at hybridization are successful, with some aborting midway and some developing fruit with no seeds.
To collect pollen, a small piece of plastic is cut into strips that will fit inside a small ziplock bag, and the pollen is scraped off the flower. When applying the pollen to female flowers, it is fastest to use hands, but if resin is present on the pollen, some serious cleaning agents may be needed to remove it. Clothes washing detergent can be used for this purpose.
Philodendron gloriosum seeds next to a typical size Anthurium magnificum or A. crystallinum seed
The time it takes for pollinated Philodendron plants to produce harvestable fruit is typically 2-3 months. However, there has been a documented cases where P. verrucosum fruit took up to 10 months to ripen (@wildaboutplants). It's unclear whether this extended embryogenesis was due to environmental factors or a species-specific characteristic. Other P. verrucosum from the same form are currently developing, providing an opportunity to observe if if this was an anomaly.
Philodendron fruit can yield hundreds to thousands of tiny seeds. The seeds will not germinate while they are covered with the sticky mesocarp inside the fruit. Our experience shows that it's possible to germinate seeds from Philodendron mamei up to three months after harvest by storing part of the fruit in the fridge. We are currently experimenting with storing Philodendron gloriosum fruit for 5-6 months to see if this storage method can be successful longer term.