Making more plants at home

Agastache

Many of your favorite perennials can be multiplied right now to make more plants for our gardens. Right now in re-purposed strawberry clamshell containers, I have cuttings from Anise Agastache, Nepeta Walker's Low, Salvia elegans, Lavender and I'm about to start Setcreasea pallida and Huskers Red Penstemon. 

Prepare a planting container with moist sand, vermiculite, perlite or sterile potting soil. Take stem cuttings about 4-inches long and remove all but the top few leaves. Make holes in the rooting medium and stick the stems into the hole. Firm up the sand, etc. around the stem. Roots will grow where you removed the leaves so be sure there is a leaf node at the very bottom of your cutting.

Nepeta cuttings with tiny roots

Shrubs that flower in the spring should also be multiplied at this time of year. Branch cuttings taken in the spring for the purpose of propagating more plants are called softwood cuttings.

Softwood is not the new tender growth shrubs have now. Test for softwood stage by bending the stem near where you would be taking cuttings. If it snaps it is ready to use. If it is flexible and does not snap it is still too green. If it is not flexible at all it is too old to use.

The methods for propagating shrubs are as numerous as the people writing about the process.

Most agree that a sharp cutting instrument must be used in order to avoid crushing the end of the stem. All but the top few leaves are removed from the cutting so no green material is under water during the rooting process.

Rooting hormones are sold in most home improvement stores. Their effectiveness diminishes with time and they no longer work at all after six months. If rooting hormone is used, the cutting is dipped into the powder or liquid and shaken off. Too much rooting hormone reduces the possibility of rooting. 

Quince cuttings

Cuttings are placed in a pre-moistened sterile medium such as perlite or in sharp sand that has been well rinsed. Which ever rooting medium you use, make a hole in it with a pencil and put the cutting into the hole, then firm it in by pressing sand, peat or perlite firmly around the cutting.

Here are directions for a rooting bucket from “Mrs. Whaley and Her Charleston Garden.” Put two inches of gravel in the bottom of a one gallon plastic bucket. Using a sharp knife, cut slits in the bucket just at the top of the gravel. Fill the bucket to the top with sharp sand. Fill with water and let drain until the water is clear. Make holes in the sand and stick the cleaned cuttings in the sand. Keep the rooting bucket in the shade and check for water periodically.

Some gardeners keep the cuttings moist and warm by covering with a plastic bag or the top of a clear plastic bottle.

Forsythia, bursts with yellow flowers in early spring. Experienced gardeners find that they can take branch end cuttings and stick them in the ground where they want them to grow. They can also be rooted in peat moss, perlite, peat moss and sand.

Flowering Quince or Chaenomeles speciosa, locally called Japonica can be rooted the same way. The old-fashioned variety has pink-orange-reddish flowers that bloom at the same time as Forsythias. New cultivars: “Texas Scarlet,” has tomato-red blooms; “Cameo” has pink flowers; and “Jet Trail” has white flowers.

Roots grow on branch end cuttings in peat moss or sand, within one or two months. Carefully check one cutting after a month. Plant rooted cuttings in pots and then in the ground next fall.

Pink Flowering Almond or Prunus glandulosa rosea plena has powder pink flowers at the same time as Forsythia and Flowering Quince are blooming. It is also called Sinesis. Thomas Jefferson planted these shrubs in his Monticello garden in 1794. Take cuttings after flowering ends and leaves emerge; root as above.

Bridal Wreath Spirea or Spiraea vanhoutti, has branches of white flowers the same week all of the above shrubs are blooming. Take Spirea softwood cuttings are taken when the leaves emerge and root in moist sand and peat moss.

Making new plants is most likely to succeed when the cuttings are taken from a healthy plant. The desire to replace a dying plant by taking cuttings is understandable but may not work.

Propagation summary: Use a sharp knife and take three to four-inch cuttings from the growing tips. Make the cut at a slight angle just below a leaf node. Remove all flowers and the lower leaves. Dip the end into rooting hormone and put the cutting deep enough into the medium (sand, vermiculite, peat moss, etc.) that the cutting will stand up. Roots emerge from the former leaf nodes so be sure there are nodes down in the medium. Water and create a greenhouse effect with plastic bag, glass jar or clear plastic box. Place in a semi-shady spot out of direct sun. Cuttings root best at 65 to 75 degrees. Remove the covering to check on their progress, allow air to circulate and the top of the soil to dry a bit.

For rooting other types of plants, refer to the Rooting Database at the University of California, Davis Web site http://rooting.ucdavis.edu where you can search by Genus and Cultivar.