Monday, February 5, 2018

Let's Plant! Tips for Planting and Propagating from Stem Cuttings


Many plants can be propagated from cuttings including stem, leaf, and/or root.  In this post, we'll focus only on stem cuttings.  Stem cuttings are one of my favourite ways to get free plants from my existing garden. Green cuttings are from fresh growth, and typically used for propagating houseplants, herbs, and other small soft bodied plants. Softwood cuttings are taken from the branches of plants and shrubs before they mature while hardwood cuttings are taken from the more mature woody growth. For any cutting method, it is best to start with a healthy donor plant to avoid spreading issues to offspring and/or placing a weak and vulnerable donor at risk.

Green Cuttings

Green cuttings can be taken from a suitable plant at any time.  This is a popular propagation technique for annuals and other herbaceous plants which don't mature into woody stems. Green cuttings are quick to root and regrow, and rooting in water make it an easy, inexpensive experiment. Herbs are my favourite green cuttings, especially mint and it's relatives!  I am partial to the smell of Vietnamese mint and I use it as a lovely shrubby ground cover in our current garden. It's rarely eaten, but often smelled! Anything that makes weeding more enjoyable is ok with me. :) It roots easily in water or even straight into the ground if kept moist. Perfect.

To take a green cutting, select a suitable healthy stem. Ideally, it will be around 5-10cm long (may be shorter for small plants), with nodes or leaves but without any flower blossoms/buds. If you must use a flowering stem, cut off the top before rooting for a better change of success.  Use a sharp clean tool to cut the stem, and on thicker stems this can be along a 45 degree angle to maximise the exposed rooting area. Gently nip or cut to remove the bottom set(s) of leaves to expose the stem in the segment that will be buried/submerged for rooting.  Dip (optional) the cut end in rooting gel.  Place the end into a container of water or a pot of prepared soiless potting mixture to develop roots. Keep them in a warm bright (but not direct sunlight) location. For water cuttings, change the water periodically if/as may be needed. For mixture cuttings, keep moist. Transplant once roots have developed.


Softwood and Semi-Ripe Cuttings

Softwood cuttings are taken using fresh new growth, often taken in springtime.  Shrubs (especially deciduous varieties), perennial flowers and herbs, and some trees make good candidates for softwood stem cuttings.  Later in the growth cycle, stems matures into semi-ripe (semi-hardwood). These stems are still current-season growth, and are firmer and more developed, but not yet fully ripe or woody. Semi-ripe stems will be firm/hard at the base but still soft at the tip, and these types of cuttings are typically taken in late summer to early fall, but if you have a temperate climate (like ours) some plants can be cut this way throughout the year.  Climbers, shrubs (especially evergreen varieties), perennial/woody herbs, and certain trees make good candidates for semi-ripe stem cuttings.  The cutting process is similar for both types of propagation, although semi-ripe stem cuttings are typically longer and will usually root slower.

Select a healthy stem. Ideally, it will be around 5-15cm long (may be shorter for small plants), with at least one node near the cut end, but ideally more. It should not have any flower blossoms/buds. If you must use a flowering stem, cut these off before rooting for a better change of success. Tip: If you're taking multiple cuttings at the same time, pop the cut stems in a jar of clean water until you finish collecting and then recut fresh. Use a sharp clean tool to cut the stem along a 45 degree angle to maximise the exposed rooting area. Gently nip or cut to remove the bottom set(s) of leaves to expose the stem in the segment that will be buried/submerged for rooting. For larger/thicker pieces, you may also wish to lightly score the bark near the cut end for additional rooting areas.  Dip (optional but recommended) the cut end in rooting gel.  Create a hole and place the end into a container of prepared soiless sterile potting mixture to develop roots. Keep them in a warm bright (but not direct sunlight) location. If your cutting has large upper leaves, you may wish to cut some of them in half from the tip and/or control humidity to reduce moisture loss until the roots are sufficiently developed for new growth. Transplant into a container of once roots have developed before moving on to the garden once the roots are more mature and (if you've had the cutting in a controlled environment) the young plant has been suitably hardened and acclimatised.

Pineapple sage (salvia elegans) and hydrangeas are some of the easiest to root stem cuttings in our garden. I skip the potting mixture all together for both. Pineapple sage (much like my Vietnamese mint, often sniffed, rarely eaten) smells fantastic! It will happily root in water or straight into the garden as long as it has suitable moisture for settling in, and isn't fussy about the technique or season.  Hydrangeas grow well from both younger stems and hardwood, making it irresistible to take advantage of replanting trimmed broken young stems or rooting seasonal hardwood prunings.  They too will take root happily from planting straight into our garden.  Free plants? So easy!


Hardwood Cuttings

Hardwood is the final stage of current-season growth (or older) when stems are fully mature and woody. Hardwood cuttings are often taken in the autumn or winter when plants are approaching dormancy or dormant, with preference to the shoulder periods just after leaf fall or just before bud burst.I like to sneakily combine my seasonal pruning with taking cuttings, but have had hardwood cutting success all through the year in our relatively moderate climate. Climbers, shrubs (especially deciduous varieties), brambles, and certain trees make good candidates for hardwood stem cuttings.

Hardwood cuttings are often taken when plants are approaching dormancy or dormant. I like to sneakily combine my autumn/spring seasonal pruning with cuttings, but have had hardwood cutting success all through the year in our relatively moderate climate.  Select a healthy stem. Since we want the mature hardwood, we'll be cutting down well below the young green and softwood growth, and trimming that off of the top of our cutting. Depending on the type of plant and length of stem, you may be able to make several hardwood cuttings from a single stem/branch before it becomes too mature (bottom) or too young (top). Ideally, each hardwood cutting will be around 10-20cm long (may be shorter for small plants), with at least one node/terminal bud just above the bottom cut and just below the top cut.

Use a sharp clean tool to cut the bottom of the stem along a 45 degree angle to maximise the exposed rooting area. Gently nip or cut to remove any lingering bottom leaves or side shoots to expose the stem in the segment that will be buried/submerged for rooting. For larger/thicker pieces, you may also wish to lightly score the bark near the cut end for additional rooting areas.  Dip (optional but recommended) the cut end in rooting gel.  Create a hole and place the end into a container prepared soiless sterile potting mixture to develop roots. Keep them in a warm bright (but not direct sunlight) location. Transplant into a container of once roots have developed before moving on to the garden once the roots are more mature and (if you've had the cutting in a controlled environment) the young plant has been suitably hardened and acclimatised.

Tip: If you taking multiple cuttings at the same time, have a container of water handy for placing the cut ends in while you collect so that your stems don't dry out during collection before you are ready for recutting and rooting.  When you're trimming hardwood, this can be particularly handy for access or getting cuts in good position on the remaining plant and then trimming the removed stems into a good angle and node position for rooting.



Troubleshooting Tips

Cuttings are vulnerable to their ambient conditions.  Make sure that you start with healthy plants, set the cuttings while fresh, and maintain a clean, moist, warm environment for the cuttings while setting root.  Don't let your cuttings dry out whilst rooting.  Keep your water fresh and sterile potting mixture moist but not soggy to reduce the risk of water. Tenting the top of your cuttings can help retain moisture if needed and if conditions require, you may need to control the temperature.  

Things getting icky or unhealthy?  Work with clean sharp tools to minimise the risk of transferring or creating extra points for disease. In addition to starting with healthy donor plants, it may also be beneficial to treat your cuttings with a gentle fungicide or cinnamon since rooting usually takes place in moist, humid, fungus-friendly conditions. Allow good air circulation and remove any diseased/rotting material. If you're rooting in water, refresh periodically.

Struggling to get things to take root?  Double check your plant variety and cutting technique/timing to ensure things are well suited to the plant you are truing to propagate. Remember that cuttings from older stems and hardwood can take significantly longer than green cuttings to set root. Some plant cuttings may not show signs of growth until their dormant season passes (I get this often with my winter hydrangeas). If everything was well-suited and conditions were good, but your cuttings don't root as expected, don't despair. It's not uncommon for cutting to fail, especially for difficult to root plants. Make a few notes in your garden journal and try again, adjusting the technique, timing, or condition.

When the time comes to transplant, be gentle and work to reduce transplant stress like you would for any replanting and remember to harden if shifting from a controlled environment. If you are planting a new cutting rooted in water into soil, it is often more stressful than moving a soil-based plant to a larger pot or out into the garden.  Some of the water-grown roots may break or die back, and the new plant might regress a little while setting newer stronger roots into the soil. If there was a lot of growth on the top of your cutting during rooting, you may need to cut it back to help the roots settle and develop as well as promote bushy growth.  If your new plant is looking rather lanky, it may also be that the source cutting was longer than ideal. If this is a problem, you can try cutting back to encourage the plant to branch/bush out. In both cases, you might even have new cuttings to root from the trimmings! :)

No comments:

Post a Comment

Thanks ever so much for leaving us a comment! We read every one and appreciate you taking the time to say hello and share your thoughts.