5. PLANT PROPAGATION BY HARDWOOD EVERGREEN CUTTINGS
Note: In this lab exercise, you will learn procedures for propagating hardwood evergreen trees and shrubs by cutting. Work in a group of two or three students. Turn in the lab report on April 28, 2004.
The rootability of evergreen
cuttings is greatly dependent on the species involved. Most varieties of
junipers, arborvitae, taxus, and boxwood root quite readily. Pine, spruce,
and fir are readily grown from seed. However, in the interest of perpetuating
specific forms, color, hardiness, etc., these species can and are propagated
asexually. Although grafting is a common method of propagating pine, fir,
and spruce, they can also be grown from cuttings.
In general, cuttings are taken during late fall and during the winter. This, however, varies greatly and the literature should be checked for specific times for each species as in some instances, a month's difference in collection time will result in success or failure. One notable exception to the fall or winter collection is Mugo pine which roots best from cuttings taken in June, just as the candles unfold their needles. Evergreen cuttings are made from the current year's wood excluding the tender, soft tip of each branch. The cuttings should be 5-7 inches long with the lower needles removed from that portion of the stem which is inserted into the media.
In most cases, it is beneficial to treat evergreen cuttings with a rooting hormone. The hormone to use, and its concentrations is dependent on species and variety. Mugo pine is again a good example wherein hormone treatment may be beneficial to some clones and detrimental to others. Bottom heat (65-75 oF) is usually required. Although a high humidity must be maintained during rooting, a mist system is not essential.
Broad-leaf evergreen cuttings, including boxwood, holly, ivy, myrtle, spurge, gardenia, rhododendron, camellia, etc., may be rooted from current year cuttings taken from late summer to early winter. Procedures are similar to those suggested for narrow-leaf evergreens. The purposes of these experiments are:
a. To learn the techniques of propagating hardwood evergreen cuttings.
b. To determine the influence of rooting media and growth regulators on the rooting of hardwood evergreen cuttings.
1. Juniperus horizontalis 'Blue Chip' (Blue Chip Juniper)
2. Juniperus chinensis 'Mint Julep' (Mint Julep Juniper
3. Thuja occidentalis (Globe Form Arborvitae)
4. Thuja occidentalis (Pyramidal Form Arborvitae)
A. Influence of media on rooting of cuttings.B. Influence of growth regulator treatment on rooting of cuttings.
1. Prepare 40 cuttings from each of 2 species of the plant materials available as demonstrated. Dip into 0.8% of IBA.
2. Stick 10 cuttings of each species in each of the 4 rooting media.
b. 50% peat and 50% perlite
c. 50% perlite and 50% vermiculite
3. Make observations of cuttings at 2 week intervals for signs of callusing and eventual rooting.
C. Data3. Stick the cuttings into the rooting medium containing 50% peat and 50% perlite.
4. Make observations of cuttings for signs of callusing and eventual rooting as before.
Score the rooting (% rooting, number roots/cutting) in each treatment. Average the scores and discuss the outcome of your experiment. Write a lab report summarizing your data.D. Lab Report
a. Title and your name
(A brief summary of findings)
(One or two paragraphs; importance and objectives of the experiment)
d. Materials and Methods
(Plant, soil and other materials used; how the experiment was run)
e. Results and Discussion
(Data on rooting percentages and their comparisons)
(Discussions and comments on your findings)
(List literature if cited)
Table 1. Effect of plant age on rooting of selected evergreen cuttings. It was found by chance
that cuttings of apple taken from one-year-old seedlings rooted very readily. Comparisons of different
aged plants were then made with other species. Some of the results were as follows:
Species Percent Rooting 1yr 2yr 3yr Older Llex opaca (American Holly) 100 64 47 0 Pinus sylvestris (Scotch Pine) 77 8 0 Pinus strobus (White Pine) 98 51 12 Pinus resinosa (Red Pine) 62 3 7 Pinus taeda (Loblolly Pine) 46 6 0 Thuja occidentalis (American Arborvitae) 100 42 Picea excelsa (Norway Spruce) 90 50 Taxodium distichum (Bald Cypress) 95 30 10 Source: Gardner, F.E. 1930. The relationship between tree age and the rooting of cuttings.
Proc. Amer. Soc. Hort. Sci 26:101-104.
Table 2. A condensed summary of cutting propagation schedule for selected woody evergreens.
|Buxus semp. suff.||xx||xx||5-8|
|Buxus, all other||xx||xx||xx||5-8|
|Euonymus sieboldiana (ManhattanF1)||xx||xx||xx||xx||xx||xx||3-4||Filler crop (root anytime)|
|Ilex crenata, glabra||x||xx||xx||x||5-8|
|Ilex fosteria, opaca||x||xx||xx||8-10|
|Sarcococca h. humilis||xx||xx||xx||xx||6-8|
|Stranvaesia d. undulata||xx||xx||xx||6-8|
|Juniperus chinensis, upright||xx||xx||10-12|
|Juniperus chin., spreading||xx||xx||xx||10-14|
|Juniperus chinensis, sargenti||xx||xx||xx||xx||8-10|
|Taxus cusp., media||xx||xx||xx||xx||10-14|
|Thuja occid., upright||xx||xx||xx||xx||8-12|
|Thuja occidentalis, umbrac.||xx||xx||xx||xx||6-10|
|Thuja occid., woodwardi||xx||xx||xx||xx||6-10|
ROOTING RESULTS OF CUTTINGEXPERIMENTS
% of roots
Cutting Propagation Lab 2
1. Plant Materials1. Juniperus horizontalis 'Blue Chip' (Blue Chip Juniper)2. Growth Regulators
2. Juniperus chinensis 'Mint Julep' (Mint Julep Juniper)
3. Thuja occidentalis 'Techny' (Techny Arborvitae)
4. Thuja occidentalis 'Woodwardii' (Woodward Globe Arborvitae)
5. Thuja occidentalis 'Wareana' (Siberian Arborvitae)1) Commercial rooting powders3. Supplies and Tools
Check the shelves in the greenhouse lab.
2) IBA solutions
Prepare IBA solutions (in 50% ethanol) in 300 ml bottles
(Dissolve IBA in 100% ethanol, and then dilute to 50%)
3) NAA solutions
Prepare NAA solutions in ethanol or NaOH, then dilute with water.
4) Also prepare control (water) solutions.
All growth regulator solutions must be kept in brown bottles or wrapped in aluminum foils. Store the bottles
in the refrigerator until use.
5) Buy or get about 50 styrofoam cups to small aliquots of growth regulator solutions during the lab period.1) Pruning shears (13 pairs)
2) Plastic labels (one box)
3) Sharpee pens (5-6, or a box)
4) Rooting medium
A 50% perlite: 50% peat mixture (about 2 ft3)
5) Trays and cell packs
About 20 trays and 20 cell pack trays.
6) Other supplies: paper towels, etc.