A mandevilla can be multiplied by snipping a short piece of stem and coaxing it to grow its own roots, a project that needs only a pot, a bag and some patience. Each rooted cutting is a genetic copy of the parent, with the same flower color and habit. Success depends less on special products than on keeping a stem with no roots warm and steadily moist for several weeks without letting it rot.
When to Cut and Which Stem to Choose
Mandevilla roots best from cuttings taken while the plant is actively growing, from late spring through late summer. Cutting in late summer has a bonus: you end up with a small plant to bring indoors before frost, which is easier to overwinter than a large vine.
Choose softwood or semi-ripe stems. Softwood is new, still-flexible growth, and semi-ripe means this year’s growth that bends without snapping but is no longer floppy. A good stem is green to slightly woody, firm, and carries healthy deep-green leaves. Skip stems with yellow leaves, pests or sticky residue. Very old, brown, woody stems root slowly or not at all, and the very soft, pale tip at the end of a shoot may wilt and rot before it roots.
Pick a shoot without flowers or buds, because a flowering stem spends its energy on blooms instead of roots. Cut a piece about 10 to 15 cm long with at least two or three nodes, the leaf joints where roots will form. Make the cut just below a node with clean, sharp pruners. Take a few more cuttings than you need, since not every one will root.
A little planning on cutting day helps. Water the parent plant the day before so the stems are full of moisture, and cut in the cool of the morning rather than the hot afternoon. Put each cutting straight into a damp paper towel or bag so it doesn’t wilt.
Preparing the Cutting Before Planting
A cutting has no roots to replace water, yet most of its water escapes through its leaves.1Purdue Consumer Horticulture. New Plants From Cuttings – Indiana Yard and Garden Removing leaves cuts that loss, and a general rule is to strip half to two-thirds of them. Large leaves that remain can be cut in half.2Purdue Consumer Horticulture. New Plants From Cuttings – Indiana Yard and Garden On mandevilla, this usually means keeping just the top pair or two of leaves.
Start by stripping the leaves from the lower nodes, the ones that will sit below the soil. Pinch or snip them off rather than tearing the bark, and remove any flower buds at the tip.
A milky white sap oozes from the cut end, and it can irritate skin.3Plant Addicts. Are Mandevilla Poisonous? Wear gloves, and let the sap stop or blot it with a damp cloth before planting. Then dip the bottom 1 to 2 cm in rooting hormone, a powder or gel that encourages roots to form. Tap off the excess, since a thin coat works better than a thick clump.
Mandevilla can root without hormone, but rooting powder tends to speed things up and raise your success rate. Buy a product labeled for softwood cuttings, and pour a little into a separate dish so you don’t contaminate the jar with sap and damp stems.
Pot, Mix and Setup for Rooting
Use a light, well-draining mix such as half peat or coir and half perlite. Roots need both moisture and air, and heavy garden soil stays soggy. Moisten the mix first, poke a hole with a pencil, and insert the cutting so one or two leaf joints are buried. Firm the mix gently so the stem stands upright.
Cuttings root fastest with warm soil, around 21 to 27 °C. In a cooler room, a heat mat or a warm spot near (not on) a radiator helps. Give bright, indirect light, because direct sun overheats a covered pot.
Cover the pot with a clear plastic bag to hold humidity around the leaves, pushing a few sticks or skewers into the mix so the bag doesn’t touch them. A cut-off soda bottle over the pot works just as well. Several cuttings can share one larger pot or a tray with a lid, and it’s worth labeling each pot with the variety and the date.
You can also root mandevilla in a glass of water. Change the water every few days to prevent rot, and pot the cutting up once the roots are a few centimeters long, since water roots are fragile and adjust poorly to soil.
Keeping the Cutting Moist Without Rotting It
Warm, dry air pulls water out of a cutting faster, while cool, humid air slows the loss.4GrowerTalks. Managing Propagation Mist Check on covered cuttings more often in hot weather or in a dry, heated room.5GrowerTalks. Managing Propagation Mist6GrowerTalks. Managing Propagation Mist
Water the mix only when the surface starts to feel dry, keeping it moist but never wet. Soggy mix suffocates the stem base and invites rot. Open the cover for a few minutes every day or two to let fresh air in.
The cover tells you how things are going. Droplets on the inside of the bag mean humidity is high enough. Wilting leaves under the cover suggest too much heat or sun. A black, mushy stem base means rot, and that cutting should be discarded. Fuzzy mold on the soil means too little air, so vent more.
The most common mistake is watering on a schedule. A covered pot loses very little water, so it may need watering only about once a week. Check the surface of the mix, and lift the pot to feel its weight: a noticeably lighter pot is drying out.
How Long Rooting Takes and How to Tell It Worked
Mandevilla cuttings usually root in about four to eight weeks, faster in warmth. The surest signs are new leaf growth and resistance when you tug the stem very gently. A cutting that stays green but shows no growth after eight weeks may still root, so keep it going if the stem is firm. Pulling a cutting out to look at the roots can snap the new, brittle ones, so use the gentle tug test first and only unpot once there is resistance or new growth.
When a cutting fails, the usual causes are a cut taken from a flowering or old woody stem, a mix kept too wet so the base rotted, a spot too cool for rooting, or too much sun under the cover, which scorches the leaves.
Once the cutting has rooted, harden it off before removing the cover. Open it a little more each day for about a week, and watch for wilting. If leaves droop, close it partway again. Then take the cover off completely.
Potting Up and Caring for the Young Plant
When you’re ready to pot up, move the plant to a pot about 10 to 12 cm wide with regular well-draining potting mix. Choose a pot with drainage holes. Avoid jumping to a large pot, because the surplus mix stays wet around a few small roots for a long time.
Tip the whole root ball out rather than pulling on the stem, and keep the stem at the same depth it was before. Fill around the root ball with fresh mix and press it down lightly so no large air pockets are left beside the roots. Water well and keep the plant out of strong sun for a week while it settles.
Once new growth appears, begin a diluted balanced liquid fertilizer every two weeks. Pinch the growing tip to make the young plant bushier, and give it a small stake or trellis once it starts to twine.
Growth is slow at first while the roots fill the pot. A late-summer cutting usually won’t flower until the next year, while a spring cutting may bloom by late summer in warm climates. Move up a pot size when the roots begin to circle the pot.
Getting Young Plants Through Winter
The ideal winter spot is bright and cool, around 10 to 12 °C, such as a greenhouse or conservatory.7Mandevillashop. Wintercare – Mandevillashop A window in a cool attic or unheated room can work, but the darker the spot, the cooler it should be.8Mandevillashop. Wintercare – Mandevillashop Below about 5 °C, leaves may start to drop. A plant that loses leaves will usually survive if green buds remain.9Mandevillashop. Wintercare – Mandevillashop
Water very little in winter, just enough to keep the soil slightly moist, because too much water can cause root rot.10Mandevillashop. Wintercare – Mandevillashop For a small young plant, roughly a shot glass of water every one to two weeks is often enough.11Mandevillashop. Wintercare – Mandevillashop
Without a greenhouse, most home gardeners will use a bright windowsill in a cool spare room, an unheated porch that stays above freezing, or a garage with a window. Judge the spot by its night temperature rather than the daytime one. Keep the plant away from cold glass and heater vents, since a cold draught or a dry blast of warm air both cause leaf drop.
In spring, increase water and resume feeding as days lengthen. Move the plant outside only after nights stay above about 10 °C, and introduce it to sun gradually over a week or two.
Is Mandevilla Sap Safe for You and Your Pets
The milky sap can irritate skin, so wear gloves and wash your hands after taking cuttings.12PubMed Central. Secretory structures in Mandevilla venulosa Müll.Arg. Woodson Apocynaceae morphoanatomy and histochemical characterization13Botany. Articulated laticifers in the vegetative organs of Mandevilla atroviolacea (Apocynaceae, Apocynoideae)14PubMed Central. Secretory structures in Mandevilla venulosa Müll.Arg. Woodson Apocynaceae morphoanatomy and histochemical characterization Don’t rub your eyes while handling cuttings. If sap touches your skin, wash the area with soap and water. If it gets in an eye, rinse with plenty of clean water for several minutes and seek medical advice if irritation lasts.
Mandevilla is not pet-friendly. Eating it can cause stomach upset, nausea and vomiting in dogs and cats.15Plant Addicts. Are Mandevilla Poisonous? It is not likely to be fatal, but puppies can be more affected.16Plant Addicts. Are Mandevilla Poisonous? Keep rooting pots and trimmed leaves out of pets’ reach, and call a vet if a pet eats some.
Can You Propagate Patented Mandevilla Varieties
Many named mandevilla varieties sold in garden centers are patented. A plant patent lets its holder control who propagates the variety for 20 years.17University of Cincinnati Law Review Blog. Propagation Prohibited? Understanding Plant Patent Protection It bars both businesses and individual gardeners from reproducing the plant by cuttings without permission, and the patent holder can sue infringers in federal court.18University of Cincinnati Law Review Blog. Propagation Prohibited? Understanding Plant Patent Protection
Check the plant tag for “PP” or “plant patent” before propagating. Tags often say “propagation prohibited” along with a patent number. Older or generic varieties without a patent can be propagated freely, and once a patent expires after 20 years, the variety is open to everyone. For a patented plant, buying another one is the legal route.