Passiflora Passion flowers – Propagating by cuttings
Many Passiflora species are under severe threat in their natural habitats, so it is important to both propagate & share them and their hybrids, of which surprisingly few are commercially available relative to the number named. Propagation can be from Passiflora seed, which will be variable & will be hybridized if crossed with another species or hybrid. If vigorous, disease & virus resistant & free flowering, particular offspring may be named as a ‘selection’ of the species. e.g. P. ‘Constance Eliott’ or as a new hybrid e.g. P. ‘Snow Queen’. Cuttings will be identical to the parent plant whether species or hybrid. Existing hybrids are best propagated by cuttings as even if fertile their seed will almost always be variable and possibly produce inferior offspring. Note, I never use Rooting Powder or Gel. They can speed up rooting but all chemicals are best avoided, there are quite enough in the environment as it is.
- What to choose. I find softwood is fine but some may prefer using hardwood. Either way avoid sections that have too long a gap between nodes. If the plant is growing too quickly the stems are softer with more chances of rot. That said, as the plants focus on flowering and vegetative growth reduces, with shorter internodal lengths, the cuttings may take longer to root. This is why the best time for cuttings may be Spring rather than when the plants are in full flower. I know Autumn is also favoured by some and the phases of the Moon may also make difference. Some people repeatedly take cuttings of hybrids only when they are in flower over the generations as they think that repeating this makes the plants more free flowering.
- Making the cut. Using P. ‘Coral Glow’ above as an example, I make many single node cuttings (always good to use single node if you have little cutting material and two nodes gives no advantage re rooting) using a sharp scalpel. Note the straight cut at the foot and the 45° cut at the top. The 45° cut is for two reasons, firstly the angle stops water sitting on the top of the cutting and also helps you remember which end is up! I also do this when cutting long stems before chopping them up as it can sometimes be hard to see which end is which.
- Trimming. The cutting has no roots to start with so it cannot support much transpiration (pulling up of water through the leaves). This will lead to leaves wilting if the leaf area area is too large. So either tear the leaves by hand or cut them with clean scissors. Some people remove the leaves totally. Also remove growing tips, tendrils & flower buds.
- Hollow stems. Some Passiflora become hollow a certain distance back from the growing tip. I light a candle and dip the hollow end into the hot wax to seal it. This make it harder for the cutting to transpire and may speed rooting. P. incarnata is a good example of one that becomes hollow very quickly but is notoriously difficult to root. Instead gently pulling out & plant a fresh shoot, appearing usually in May, which should come out with a few inches of root. Even broken sections of root may sprout.
- Rooting medium. Do not use any type of compost or soil for Passiflora cuttings as they will be far more likely to rot. I am indebted to Carlos Magdalena for his suggestion. He uses a soilless 50:50 mix of coir and Perlite and in the bottom half of the pot puts a compost/ Perlite mix for the roots to grow down into. Water well, then place the the cuttings at least 1cm into the mix. For trickier cuttings that are more prone to rot, I just use Perlite on its own. Vermiculite, sand and other soilless options work well too. Seramis (clay granules) is another option but it is expensive and I have found it more liable to dry out at the top. Some cuttings will even take just in water on a windowsill. Change the water regularly if you try this technique. Note that the roots will be more fragile and need to be transferred to soil gently or they will snap off.
- Where to put them. In 2018 I treated myself to a Vitopod Heated Propagator with Grow Lights. Expensive but worth every penny. I run it at 24°C which works for both cuttings and seed. Heated or unheated propagators with a lid or just pots put in a quiet corner will all work (though bottom heat will speed things up) but whatever you use, keep the cuttings out of full sun and keep them damp but they don’t like too wet feet. Some cuttings like Tacsonia may do better with no bottom heat.
- Patience. It can take anything from a couple of weeks to a couple of months for Passiflora to root. Top growth usually, but not always, indicates successful rooting. Some will form an enlarged callus at the foot but still not root. If this is the case then pull them out, scratch up the callus with a scalpel and put the cutting back. This may help it produce roots.
- Potting up. Some wait till roots are visible through the foot of the pot, but really once there is any root at all transplant straight away into a pot with a 50:50 mix of soil and Perlite. This gives the cutting nutrition and also is a nice easy free draining soil mix for the roots to push through. Again keep in shade and bottom heat will speed everything up. Once the cutting is growing well increase natural light till it can take full sun, unless it is one of the cool growing shade loving Passiflora.