CASE STUDY FOR ROSES

Growers of roses and other plants always have several varieties that are favorites.  From these favorites there may be some which are desirable to propagate to make new plants. This is especially true when older varieties are no longer commercially available.

Propagation of roses by cuttings:
Propagating roses (and other plants) by rooting softwood cuttings is a simple way to obtain more plants. Some varieties are usually self-rooted. Other varieties have the upper portion budded or grafted onto a root stock; these root stocks are usually propagated from cuttings. "Old Garden Roses", shrub roses and miniature roses may be grown on their own roots. Modern hybrid teas and floribundas are less predictable.

Many rose varieties cuttings are best taken from young stems of the current seasons growth. When taking cuttings from "non-stop" varieties select stems on which the flowers petals have just fallen. For "annually flowering" varieties take cuttings in the late Spring after the flowers have faded.

Rooting rootstock for roses used for budding and grafting:
Some roses are propagated by taking a cutting or a bud from a selected varierty (scion) and attach it to a selected rootstock (stock). If you intend to bud or graft plants the rootstock plants are produced from cuttings. First root the rootstocks from cuttings then perform the budding or grafting operations. Some growers graft and root the root stocks at the same time; this technique is called stenting.
 

Rooting rootstock for many plants propagated by budding and grafting:
Grafting success may be improved using Hortus IBA Water Soluble Salts rooting solutions (see more information to improve grafting unions):
Success of a graft union depends on the establishment of a callus bridge between the cut surfaces of scion and stock, and the subsequent establishment of a functioning vascular cylinder connecting scion and stock. Initial callus formation appears to develop about equally on the cut surfaces of both partners, arising not from the cambial layers but from parenchyma cells, mostly in the wood just inside the camblum. Soon after scion and stock calluses have merged, callus cells just below the cambial cells of the scion begin to divide in the same plane as the camblum. Waves of cell division proceed from the top down, suggesting that a regulatory stimulus moves to the cut surface from the growing-shoot tip. Callus parenchyma cells inside the new camblum cylinder re-differentiate into functioning xylem cells. Last of all, the new cambium begins producing phloem cells.

BASAL QUICK DIP METHOD

BASAL LONG SOAK METHOD

Dip the basal end of the cuttings 3/4 to 1 inch into the Rhizopon AA dry powder rooting hormones, one by one or in small bundles. Make sure that the powder is evenly distributed in a thin even layer (1/32 to 1/16 inch) over the whole base of the cutting. Too much powder on the cuttings might result in excessive rooting where there is surplus powder. Root formation can be expected all over the part of the cutting covered with the powder. Avoid contact between the powder and foliage and other over ground parts of the stem since it may cause phyto toxicity. Tap off the excess powder. Plant the cuttings immediately in moist media. After treating cuttings take care of them.

Rates for roses using Rhizopon AA dry powder rooting hormones, usually
Rhizopon AA #1 or Rhizopon AA #2 (best) early in the season
Rhizopon AA #3 (for harder to root cuttings) later in the season.

Rates: using Rhizopon AA dry dip rooting hormones by plant variety see the Rates (Dry Dip) by Plant Variety and Type

TOTAL IMMERSE METHOD
used at the same rates as the Spray Drip Down

First totally immerse the cuttings in the fresh Hortus IBA Water Soluble Salts solution for a few seconds then plant them. You can use a basket to dip the cuttings in a tub. Prevent bruising by not placing too many cuttings in the solution at once. Allow time for the solution to dry on the cuttings before watering, misting or covering. The temperature of the solution should be at least equal to the cutting temperature. A cold solution temperature causes the stomata of the cuttings close; the amount of active ingredients absorbed is reduced.
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Rates for roses if you use Hortus IBA Water Soluble Salts: 3/4 to 1-1/4 gram per liter of water.

Rates: using Hortus IBA Water Soluble Salts by plant variety see the Rates (Spray Drip Down and Total Immerse) for Plant Variety and Type

There is a major benefit to use this method. The bud eyes keep dormant until the root is developed thereby achieving a stronger plant.

Planting and Taking Care of the Cuttings:

Fill the pots firmly with a sterile potting mix which is moist not soggy. Several cuttings can be planted in the same pot. Treat the cuttings with rooting hormones using the Rhizopon AA dry powder rooting hormone Dry Dip Method
or
Hortus IBA Water Soluble Salts (to make fresh solutions) Solution method.
Place the cutting in the hole and firm the soil very tightly around it.

To prevent the cuttings from dehydrating through the leaves and stems the cuttings are often propagated under mist systems in controlled greenhouses or tunnels, in cutting trays covered with plastic.

Maintain adequate moisture in the soil and air humidity. Commercial growers usually use mist system to prevent wilting. A fine mist of water is sprayed over the cuttings for a few seconds every few minutes. Another method is to stick the cuttings in pots or trays then cover and seal the pot with clear plastic; a poly bag works well when covering a small pot. When available use a misting system.

Construct "greenhouses" for the cuttings using empty 1 or 2 liter soft drink bottles small pots or cups which are larger in the top then the bottom of the soda bottle.
For old style soda bottles: use a knife to cut off the bottom of the bottle where the solid-colored section is joined to the clear section. For new style bottles: cut off the bottom. Keep the bottle cap. Use pots which fit into the bottle bottom.
The top of the bottle should just fit snugly inside the pot rim. If you have the old style bottle bottoms, use them as a pot holder.
Place the top from the soda bottle over the cutting and press it gently into the soil. Make sure that there are no gaps through which evaporation could occur. Put the cap on the bottle, but do not tighten.
After a few hours check the bottles to make sure there is some moisture condensed on the inside of each. If not, your soil may not have been moist enough and a small amount of additional water should be added.
Place the bottles in a bright light but not in direct sunlight as below. In the hot Summer keep in bright shade to prevent over heating  the tender plants.

Place the cutting pots in a place where heat does not heat the cuttings. The cuttings should have bright light to allow photosynthesis. In the spring many varieties will develop roots in ten days to two weeks. Some varieties can be rooted in three to four weeks. In the winter roots may form in four to eight weeks. To determine if a cutting is rooted you can tug lightly on it; if it resists being pulled out of the pot it is likely rooted.

Cuttings which are treated by Hortus IBA Water Soluble Salts by the Total Immerse Method will develop roots fast and have a delayed bud sprout. The cutting is initially putting its energy to making roots before making leaf.

Take care of the cuttings. Acclimation of the newly-rooted plants should be done gradually. After the cuttings are rooted remove discontinue the mist or remove the cover. Harden them off for a few days by putting the pots in the shade in a cool place. Once the plants have adjusted to normal humidity they can be place in regular pots to continue their growth. After the plants have a good root system move them into brighter light.

Stenting:
Graft shown with scion top and rootstock bottom

Air layering involves the wounding the stem of the plant while it is on the stock plant. Treat the stem then cover it. Roots form in the covered area. The tip of the stem sticking out of the covered area will continue to grow. It will soon become a new plant with it's own roots. The roots form at the wound. After the roots form sever the stem from the stock plant.

Use Rhizopon AA dry powder rooting hormones to treat air layers. Apply using a clean soft brush using Rhizopon AA #2 or #3 dry powder rooting hormones. If using cocoa fibers make sure the processing salts have been removed. As an alternate you can use  Hortus IBA Water Soluble Salts @ Soak the moss or cocoa fibers in 150-500 ppm IBA. Wound the stem of the cane. Apply the fiber. Cover the fibers with aluminum foil to protect against drying out.

See: Other Special Techniques

Root regeneration of rose plants is promoted by application of Rhizopon AA solutions. The active ingredients in applied to root segments increase the number of regenerated roots as well as root length.

A rose crop often starts with transplanting dormant material. Problems with survival and bush development may be due to bad root re-growth (root regeneration). A treatment that would decrease the time to new root initiation and increase the number of roots or the elongation rate of the roots should increase the chances of successful establishment and early productivity of rose plants. Re-growth of roots is generally known as root-regenerating potential (RRP) which is defined as the capacity of roots to elongate or initiate and elongate new lateral roots.

Growers use Rhizopon AA when transplanting rooted rose bushes to improve early flower yield. Roses, Inc. growers produce 80% of the rose flowers grown in the US. These growers follow the lead of their Dutch counterparts to increase flower yield by using Rhizopon AA. The following is excerpted from a technical report published in the Roses Inc. Bulletin (October 1992).

←The photograph on the left is an un-treated one year rose bush. On the right is a treated one year rose bush. Notice that the treated bush has more fibrous growth and greater root mass.
Traditionally American rose growers allowed one to two years of growth before transplanting rose bushes. Without special treatment a young rose transplant uses its energy to rebuild a root system instead of entire plant growth. Without a strong root system the plant has reduced ability to feed and receive water therefore subject to stress and possible mortality.
Dutch growers, for over fifty years, transplant half year old rose bushes. To improve root regeneration and increased first year flower yield when transplanting bare root rose bushes the roots are immersed in a solution containing Hortus IBA Water Soluble Salts. The roots are not cut back except for damaged or broken roots. Living roots contain stored carbohydrates.

HORTUS IBA WATER SOLUBLE SALTS FACT SHEET
(download Fact Sheet)