Grafting with Stenocereus griseus & Stenocereus pruinosus.
General Growth Parameters
Light intensity tolerance:
Daylight Hours: 8-16
Shade tolerance: Tolerates partial shade, benefits from at least a five hours of direct sun. Stems will become thin in low light and also tend to be more prone to rot and pest infestation.
Water tolerance: Tolerates massive amounts of rain if not cold, but will rot if waterlogged for extended periods. These 2 species grow in ground outdoors in Taiwan which gets some of the heaviest rain on earth.
Drought tolerance: Can tolerate true dry soil for a long time. When used as a grafting stock it is not advised to let stocks dehydrate too much.
Growth speed: Both species are fairly fast as a rootstock. I would say maybe medium fast if not fast. They are especially suited for very large scions such as big crested plants. They can support a lot of weight and we use these species for our largest of scions.
Stenocereus is a fast enough genus on its own roots, though for mutations it may be beneficial to speed up growth via grafting. We do in fact graft variegated plants to take cuttings from in the future. They can be grafted by any means and procedure, we prefer flat grafts for effectiveness and ease of procedure. Follow standard flat grafting procedure found here: Grafting Cacti.
Weaknesses of Stenocereus griseus and Stenocereus pruinosus as a rootstock
* Not very cold tolerant, should be kept above 1C to live comfortably and about 10-15C to grow fast.
* Slightly slower than the tropical vine cacti stocks, but much more robust and long lasting.
Grafting onto Stenocereus rootstocks
Follow standard cactus grafting procedure with this stock. It is one of the easiest rootstocks to graft too so long as you are grafting onto new active growth. You may view the procedure page here: Grafting Cacti.
Here are some pointers to make grafting to Stenocereus easier
* Only graft during the warm season when plant is actively growing. New growth is obvious with this species at it will be slightly blue in colour in contrast to the previous yearís growth which will be green.
* Squeeze the tip gently and make sure it feels slightly soft, yet still firm. Dehydrated stems with ribs that bend when you cut are too dehydrated. A knife should slip through without having the stem flex with the blade.
* Donít use older growth as it will be too woody and future scion growth will be far slower.
* Keep humid but in very good air flow. This cactus has a bigger cut surface area and thus a bigger invitation to fungus spores. Rust is the most common thing witnessed on cut surfaces. To avoid it provide more fresh air and once graft heals, drier air.
* Removing all areoles will indeed help speed, but is not necessary.
Have the stocks growing in preferably 20C + temperatures for a good month to get it actively growing. When you see over 5cm of new growth you can cut into that for grafting, more is probably better. Keep well hydrated at all times before grafting, and stop watering once grafted until scion is well healed (1-2 weeks). Stenocereus like sunshine, so growing in good light is ideal for growing thick healthy plants. Stenocereus grow to over 40cm in diameter if left for a while in good conditions. But for grafting anything under 10cm should be great.