Cacti propagation

By: Jennifer Brause


Cacti can be propagated in many ways. Propagation is done by cuttings, bulbils and offsets, seed, grafting, and division. Cuttings, division, and bulbils and offsets are the easiest, where as seeding and grafting are the hardest. However the type of propagation is dependant on the species of the cactus. For example Ice plants and Christmas cacti are best propagated by stem cuttings. Each method has many different ways to carry out the propagation.

One of the easiest ways to propagate cacti is by cuttings. Cuttings are pieces of cactus stem without roots. This method provides larger plants much more quickly, but fewer plants can be obtained. The most common way is stem cuttings. Most stem cuttings are rooted in the spring to summer season. Crassulaceae and Ice plants are propagated during the winter. Size of the cutting is variable by cactus, on Christmas cacti a few stem segments may be used while on Columnar plants a cutting may be as long as a meter. When taking cuttings it is a must to remember which was the top and the bottom of each piece, apiece that is planted upside down will not grow. A simple way to remember is to cut the bottom of each piece at an angle and the top straight across. For pad-forming or branching cacti, the best place to cut is at the joints so that the mother plant is not disfigured. Allow cuttings to dry for a few days before placing in a rooting medium. The larger the surface the longer the cutting needs to dry. This allows the cut surface to heal, or callus. Calluses prevent rotting when the cutting is placed in a rooting medium. Another way to prevent rotting is to dip the new cuttings in garden sulphur before planting. Columnar cacti should be stood up in an empty container to heal off so the stems don’t bow up. The most common rooting medium is pumice, an aerated volcanic rock. Other rooting medium is equal parts of peat moss and sharp sand. The cuttings should be placed in a sunny location, but not exposed to direct sunlight and watered occasionally. It is recommended to keep cuttings in a propagator with a top to retain humidity until they are established. To make a propagator place a pot inside an inflated polythene bag or the top half of a clear plastic bottle can be placed over it. Be careful when propagating Euphorbias, they have a poisonous/milky sap which can be congealed by placing in cold water, healed off and placed in pumice.

Some cacti can be propagated by bulbils and offsets. Some agaves and aloes form bulbils on their flowering stalks. These can be removed and rooted during warm weather. Some plantlets often bear juvenile roots that can also be rooted in pumice; this type is produced during the winter. Globular cacti have offsets or pups if unrooted; you can root in pumice, if rooted pot up in the same growing mix. Offsets can be easily pulled or cut off the main plant. These too need to dry for a few days. The main plant often benefits form removal of offsets, offsets divert energy form the main stem. A great mix to use is 1 part potting soil, 1 part sharp sand or decomposed granite and 1 part pumice. This mix gives excellent drainage.

Propagation by offsets. Select plant to propergate. Gently remove from containers. Gently pull offexts of of the main plant.

Propagating by seed is an inexpensive but slow way to introduce unusual and exotic cacti. Seeds may be collected from any cactus plant that has flowered by simply removing the ripe pods or the fastest way is to purchase them from a Nursery, mail-order houses or specialized cactus suppliers. Fully mature pods are cut open and the seeds are squashed out onto a piece of paper towel to dry. Most cacti can be raised from seed. A basic method for home gardeners is as follows: 1. Obtain a plastic pop bottle, cut in half, drill drain holes. 2. Formulate a germination mix of 1 part perlite/pumice and 1 part vermiculite and a dash of Osmocote fertilizer. 3. Scoop up mix in pop bottle germinator, drench with fungicide mixed in distilled water. 4. Sow seed. 5. Cover with plastic wrap or enclose in a plastic bag with seal, place in a cool, well-lit window. 6. Remove plastic wrap or plastic bag when seedlings begin to mature and keep well watered. 7. Divide seedlings, pot into growing mix. Another way is the seeds are sown in top of a pot with dry cactus mix and are sprayed with a fungicide then covered with a layer of silica sand. This case don’t water after 2 weeks the pots get a good soak Seedlings don’t need to be transplanted until they almost touch each other, this may take from one to many years. Special treatment is taken for Pediocactus and Sclerocactus. These cacti have a hard seed coat. There is 2 ways to over come this. One way is to rinse the seeds with water and sow them in sterile cactus soil in a glass; the seeds are then covered by a thin layer of sand and sprayed with fungicide. Place the glass in a sunny place. Seeds that do not germinate after 2 to 3 weeks are removed and cleaned with water and fungicide, and then the hilum can be pricked off with a needle or a sharp knife and sown in a new glass. The other way is using the “baggie” method. Seeds are cleaned and sown on a piece of kitchen roll paper that is folded three times. Paper is moistened with fungicide, seeds are sown and the last fold is closed. The “envelopes” are put in a plastic bag. It is important to check the envelopes every day and if you see a seed that is germinating it must be transplanted to a pot with moist sterile cactus soil, spray with fungicide and cover the seed with sand. Don’t let the soil get dry for a while. The seedlings should not be introduced to full sun for at least one year. After time potted seedlings can be slowly introduced to brighter and brighter light, until they are growing in a location with full sunlight

Grafting produces unusual growth forms and provides a decay- resistant stock for certain kinds of cacti. Grafting also can save a plant with a rotted stem or root system. Grafting is done for many reasons. One reason is that some cacti lack chlorophyll. Another is for cacti that are difficult on their roots such as pincushion cacti, which tend to rot off on their own roots. Select the cacti to be used as the stock and scion and make appropriate cuts with a sharp knife. The grafting should be done when the stock is actively growing. It is important to make sure that the surfaces are clean, fit closely together and do not dry out. Hold the scion in place with string or rubber bands. Keep the plant in a moist, warm place so the union will not dry out and force the graft apart. It takes about two weeks for the stock and scion to unite. After that time bindings can be removed. There will be a shrinking and discoloration of the union if the graft has failed. Using peat moss propped up around the graft will help keep the graft moist. There are three common grafts that are preformed. Flat grafts are the simplest. These are used on plants with fleshy stems. The stock is first cut flat with a single clean cut above soil level. The material to be grafted is also cut cleanly across and the cut surface placed on the top of the cut stock in a way that at least part of the vascular elements on both pieces are in contact. The graft is held in place with a rubber band. Side grafting is used for thin material in which the stock and scion are both cut at an angle to increase the area of cut stem and increase the chance of the vascular elements making contact. Split grafting is also good on thin material. The end of the scion is cut into a wedge shape and inserted into a “V” shaped incision in the stock. The stock is then bound tightly with cotton to hold the two parts together. A basic grafting technique is as follows: 1. Choose a worthwhile robust understock. 2. Choose a scion to match the understock. 3. With a knife cut the scion and understock. Carefully bevel the top of the understock. 4. When the scion and understock are ready, remove a final thin slice form each. 5. Press the scion and understock together with vascular bundle rings matched. 6. Drape strings weighted with hardware nuts of the scion. 7. Keep the graft out of hot direct sun. In about a week you will know if the graft has taken.

Many species of cacti form mats or clumps or thick tuberous roots and may be propagated by division. Some plants will disintegrate to a handful of cuttings as soon as removed from their pot, and good pieces with roots can be potted up individually. Repotting must be very gentle or the cutting placed into the desired pot size. Other cases a thick tuberous branching root will be revealed and this can be divided into two or more pieces. Each piece should have growing points and vigorous roots. This division is best carried out while the plant is dormant and dry, or excessive bleeding of sap may weaken it. Cut surfaces can be dusted with a fungicide and allowed to dry for a few days of the tissues to seal and callus over.

In conclusion cacti can be propagated in many different ways. Cuttings, bulbils, offsets, seed, grafting, and division are the common methods used. Each cactus has a certain type of propagation that is right for it.

Get propagating!!

Work cited

Jensen, Benny Moller “Propagation of hardy cactus, other succulents and alpine plants” Copyright © 1998-2005.

The University of Arizona “Propagation of Cacti and Succulents” Copyright 1998

California Cactus Center “Propagation Basics: Taking Offshoots” Copyright 2002-2005