Cloned Dogwood Project Background
The USA National Phenology Network’s (USA-NPN) plant and animal observing program,
Nature’s Notebook, has roots in repeated observations of cloned lilac phenology, hearkening
back to the 1950s. We continue this legacy today, through the promotion of both cloned lilac
and dogwood plants for observation. Cloned plants are genetically identical, grown from the
same “mother plant.” The value of observations of cloned plants is that differences in individual
plants’ phenology can be attributed to differences in local environmental conditions, rather
than to differences among the plants themselves. These data help scientists better understand
plants’ responses to the changing environment at both regional and continental scales.
How are plants cloned?
Plants reproduce either by sexual reproduction, through seeds, or by asexual reproduction, by
grafting or budding. Grafting and budding join two plant parts together to form a new plant. One
of these includes the scion, which consists of a piece of shoot with dormant buds that will
produce the stem and branches. This is joined through grafting to the rootstock, or stock, which
creates the plant’s root system and sometimes the lower part of the stem. For a successful graft,
the scion and rootstock must be compatible, both must be at the right physiological stage, the
inner layers between the wood and bark of the stem (the cambium) must meet, and the place
where the scion and rootstock are attached must be kept moist until the wound has healed.
There are many different ways to graft scions and rootstock, which you can read about at
ag.arizona.edu/pubs/garden/mg/propagation/grafting.html.
The USA-NPN invites you to monitor cloned plants through the Cloned Plants Project by
planting and monitoring a native flowering dogwood “Appalachian Spring” (Cornus florida).
Dogwoods are more suitable than lilacs for warmer locations such as the southeastern United
States.
The data that have historically been collected on cloned plants, including lilacs and
honeysuckles, represent the only geographically extensive on-the-ground data set in the United
States. These observations have served as the basis for a number of scientific studies on the
relationship between climate conditions and the onset of spring. These relationships are
valuable in predicting how spring onset may shift
under altered climate conditions. A geographically
extensive set of repeated observations of cloned
individuals, following standardized protocols, has
great value for many applications, including predictive
models for timing of spring arrival.
Flowering dogwood (Cornus florida) ‘Appalachian
Spring’ is a deciduous, multi-branched shrub or small
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tree that reaches a height of 20 to 25 feet tall with a crown spreading up to 20 feet. Leaves are
opposite, simple, medium green and slightly larger than the native flowering dogwood. Veins
are parallel and follow the elliptical shape of the leaf. In the fall, the leaves turn red or purple.
The yellow, clustered flowers are inconspicuous and surrounded by four large, showy, white
bracts. The fruit is a yellow to red drupe (a fruit with an outer fleshy part and a hardened shell
inside, such as a cherry) that holds 1 to 2 cream-colored, elliptically-shaped seeds (more info on
basic botany at en.wikibooks.org/wiki/Botany).
Dogwood Planting Instructions
Caring for your new dogwood:
Your new dogwoods are bare root saplings, about 12 inches long,
which require care before you plant them. The dogwoods have
arrived with material around the roots to keep them moist. Please
make sure you keep this material covering the roots until you are
ready to plant, and plant them as soon as possible to ensure survival.
If you can’t plant immediately, saplings should be kept in in a
refrigerated unit at a temperature between 33 and 38 degrees F with
85 to 95 percent humidity. If no refrigeration is available, saplings can
be stored at 38 to 50 degrees F for 2 to 3 weeks, or at 50 to 75
degrees F for 3 to 5 days. Temperatures above 85 degrees F will
quickly kill stored saplings. You can watch Arbor Day Foundations
instructional video about planting bare root saplings at
www.arborday.org/trees/planting/bare-root.cfm.
Selecting where to plant your dogwood:
Choose a site for your dogwoods that is well-drained but does not get extremely dry. Soil high
in organic matter is best. Dogwoods can be planted in full sun or partial shade though partial
shade is best (morning sun in particular). Dogwoods are typically an understory tree in the wild.
Dogwoods are easy care trees that will likely bloom by their second year, but sometimes will
bloom in their first year.
Planting your dogwood:
Before you plant, cut off any damaged roots with a sharp knife, and soak plant roots in water
for 3-4 hours.
Bareroot saplings can be planted with a planting bar (often called a dibble), shovel or mattock.
Saplings should be planted no deeper than the depth they were planted in the nursery. You can
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tell the depth in the nursery by a slight color change on the stem. Make sure the hole is big
enough to allow the roots to be spread out, at least 1 foot wider than the root spread. Roots
should be pointing straight down in the hole and not “J” rooted (roots bent back pointing
towards the top of the hole). Fill with same soil that came from hole-mix topsoil and subsoil
together.
From “Planting Landscape Trees and Shrubs” Michael N. Dana, Purdue University Cooperative Extension Service,
West Lafayette, IN (1995).
Maintaining your dogwood:
Place a layer of 3-4 inches of mulch around your newly planted trees, taking care to not pile the
mulch too high on the trunk of the tree. You may fertilize your dogwoods at the time of planting
and first watering, but do not fertilize again until the second year. Watering during winter is
rarely necessary. In summer and fall, water once or twice a week. When watering, thoroughly
soak root-zone area and beyond. After the first growing season, rainfall should be adequate
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except in times of drought. Fertilize trees in the second year twice a year, in February and midJune. Fertilize with 3 oz of nitrogen per 100 sq feet of ground area surrounding tree, and water
after fertilizing. Do not prune your dogwood until the second year.
Other resources:
Find your local extension office: www.csrees.usda.gov/Extension/
For more information about Dogwoods:
utextension.tennessee.edu/publications/documents/PB1670.pdf
For more information about planting bareroot tree and shrub seedlings, contact the South
Carolina Forestry Commission or the National Wild Turkey Federation’s Project HELP (Habitat
Enhancement Land Program) (800) 843-6983
For more information on care of your dogwood: www.aces.edu/pubs/docs/A/ANR-1077/
Monitoring Your Dogwood
Now that you have planted your dogwoods, make regular observations to track the timing of
their leafing, flowering, and fruits (phenophases).
To get started…
1. Sign up as a USA-NPN observer at www.nn.usanpn.org- Become an official participant
with Nature's Notebook and set your username and password. All you need is an email
address and Internet access.
2. Make observations - We invite you to track several phenophases of your dogwoods,
including:
 Leaves: breaking leaf buds, leaves, increasing leaf size, and falling leaves
 Flowers: flowers or flower buds and open flowers
 Fruits: fruits, ripe fruits, and recent fruit or seed drop
For a description of each phenophase and to download datasheets for your
dogwoods, visit our webpage at www.usanpn.org/Cornus_florida-appalachianspring.
3. Report your observations - As you collect data during the season, log in to your
Nature's Notebook account and enter the observation data you recorded.
More details on the specifics of observing at www.usanpn.org/nn/guidelines.
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