Nepenthes stem cuttings: from climbing vines and rosettes

Why cuttings, and why not seed

There are two ways to clone a Nepenthes: tissue culture and stem cuttings. The ICPS stem cuttings page explains that large nurseries use tissue culture to produce plants in huge numbers, but that it is difficult for hobbyists, who rarely need hundreds of one plant. Cuttings are the usual method for hobbyists and small nurseries ^[1].

Seed is a poor substitute when you want a particular plant. Nepenthes have separate male and female plants, plants are rarely labeled by sex, and a pair that flowers together is usually two different species, which is one reason there are so many hybrids ^[2]. Seedlings vary widely, and the largest may be accidental hybrids ^[3]. A plant from seed takes 3 to 5 years to reach display size ^[2]. The ICPS seed guide points out that some of the easiest hybrids, such as N. × Superba and N. × Mixta, are hard to buy and often have to come as cuttings from friends, and it recommends that beginners start with tissue-culture plants or plants grown from cuttings ^[2]. The Nepenthes overview covers the groups and species, and seed is covered in sowing seeds.

When to take cuttings

Any time of year works, but cuttings from a plant in active growth seem to root faster and more often. The ICPS page puts this down mainly to the parent’s health: a plant that grows well in your conditions will usually give cuttings that root well in them, while a struggling parent suggests the temperature is wrong for rooting too ^[1].

Choosing the stem

The ideal donor has a tall climbing stem with leaves spaced well apart, plus a new rosette of leaves at the base. You can then take the climbing stem, whole or just its tip, and leave the rosette to carry on ^[1].

• One new plant. The actively growing tip with 2 or 3 leaves is the best cutting. If the stem left behind still has green leaves, it will usually resprout near the cut, though the parent takes a few months to look presentable again ^[1].
• Many new plants. Cut off the entire climbing stem, leaving only the basal rosette, and divide the stem into pieces ^[1].
• No basal rosette. Either take cuttings now but leave at least 4 green leaves on the stem, or, with a long stem, lay the pot on its side so the stem runs horizontally or hangs down; within a few months a new basal rosette should sprout, and the whole climbing stem can then be removed ^[1].

Rooting medium

Use a loose, free-draining mix that is neutral to slightly acidic and low in nutrients. The ICPS lists long-fiber sphagnum, a 50:50 mix of long-fiber sphagnum and perlite, or a 50:50 mix of coir and perlite ^[1]. Coir must be a brand leached by several monsoon seasons of rain to remove its salts, and dried “sphagnum” must really be sphagnum: the sheet moss sold for lining hanging baskets is not ^[1]. Keep the medium damp, not soaking and not standing in water ^[1]. See water for water quality.

Making the cuts

A Nepenthes stem can only produce a new shoot from a growth bud, which sits a few millimeters above the point where a leaf joins the stem. Every cutting therefore needs a leaf node or the growing tip. Roots form at the cut end at the bottom of the cutting, not, at least at first, at the nodes ^[1].

1. Use a new single-edged razor blade, changing it often if you cut many plants. A fresh blade cuts cleanly without crushing the stem ^[1].
2. Make the cuts under water, so air does not block the stem’s water-conducting tissue at the cut ^[1].
3. Cut far enough above each leaf that the growth bud stays on the cutting ^[1].
4. Choose the cutting length by the age of the stem, as in the table below ^[1].
5. Make sure each cutting has at least one growth bud below the surface of the medium. That bud lets the plant resprout if the top breaks and is where a new basal rosette will form. The ICPS page describes a cutting whose only bud sat about 5 cm above the soil and grew rosettes in mid-air, leaving it easy to snap ^[1].
6. Remove pitchers if they make the cuttings hard to fit in a bag. Halving each leaf to cut water loss is optional when the cuttings will be sealed in a bag ^[1].

All rows: ^[1].

Optional extras

Some growers split the bottom 10 mm or so of the stem under water and wedge a little sphagnum into the split, which gives more surface for roots; the ICPS page stresses keeping the blade pointed away from your body ^[1]. Rooting hormone is also optional. The ICPS authors did not find it useful, and too strong a dose can stop roots from forming: a cutting that forms a callus but no roots points to that. If you use it, never dip cuttings into the container; pour a little onto paper or apply it with a brush, and use the dose recommended for softwood cuttings ^[1].

Aftercare and waiting

1. Label the pot with the plant and the date ^[1].
2. Seal it in a plastic bag so the cuttings cannot dry out ^[1].
3. Keep the bag in bright light but out of direct sun ^[1].
4. Remove failed cuttings as soon as you notice them, so they do not start rot ^[1].
5. Wait for new growth before taking the cuttings out of the bag and potting them ^[1].
6. Pot rooted, growing plants into their growing pots and move them to a terrarium or a partly opened bag to adjust them to lower humidity ^[1].

Rooting takes anywhere from a month to a year, depending on the parent’s vigor, the species and the conditions. Some species simply root slowly, and as long as the leaves stay green the cutting still has a chance ^[1]. The ICPS page publishes no success rates, only the comparisons between cutting types above; its photos show a N. bellii tip cutting 18 months after it was taken ^[1]. For weaning plants off high humidity, see terrariums and humidity. Once potted, rooted cuttings go into the conditions that suit their group. For plants kept in the house, the ICPS windowsill page names lowland species such as N. rafflesiana and highland ones such as N. alata and N. ventricosa as good choices, and uses a heavier mix of about 75% sphagnum and 25% perlite in larger pots because house plants dry out quickly ^[4]. If a plant then fails to pitcher, see Nepenthes not making pitchers.

Cuttings from a basal rosette

Some Nepenthes rarely grow a climbing stem, which makes cuttings risky. The growing point and all the leaves are packed into about 2.5 cm of stem or less, the plant often has only one rosette, and each attempt yields one tip cutting ^[1].

1. Aim to take the growing tip with one or two leaves while leaving about 4 good leaves on the parent. Because leaf bases overlap along the stem, it is hard to see where the true tip is ^[1].
2. Cut cleanly through the stem below the fourth leaf from the tip with a razor blade or scalpel; there is no room to spare. The third and fourth leaves often peel away because they were attached below the cut ^[1].
3. Pot the cutting, probably only about 1 cm of stem with a leaf attached, in the same mix as other cuttings. Hold it in place with a U-shaped piece of wire and bury the stem 0.5 to 1 cm deep in sphagnum ^[1].
4. Bag it and treat it like any other cutting ^[1].

The ICPS example used the hybrid ‘Peter D’Amato’, cutting between the third and fourth leaves so that the parent kept 4 leaves and the cutting got three, rooted in 50:50 sphagnum and perlite. The author reports good results but warns that the operation is hard on the parent and often sets it back half a year to a year ^[1].