Late Fall!
Male-Female differences color the show of berries on
shrubs in a hedge
Dear Janet,
I'm planning a hedgerow with plants that will attract
birds. My question is whether all fruiting shrubs require male and
female plants in order to set fruit. I know that certain plants do,
such as northern bayberry ("Myrica pensylvanica") and
holly ("Ilex verticillata"). But what about chokeberry ("Aronia
arbutifolia"), spice bush ("Lindera benzoin"), American
cranberry bush ("Viburnum trilobum"), fragrant sumac
("Rhus aromatica"), and Oregon grape holly ("Mahonia
aquifolium")?
S.L.
Dear S.L.,
Flowers have structures we've dubbed female and male -- a female
pistil can produce fruit if it's fertilized with pollen from a male
stamen. Many plants grow both pistils and stamens, so that even
solitary individuals of that type can produce ripe berries. Many
shrubs, including chokeberry, cranberry bush viburnum and grape
holly are in this group.
Spice bush is different. Like true holly, it's dioecious -- a
single plant produces either pistils or stamens but not both. In
such species we call a plant that has pistils a female and
understand it can't set fruit unless a stamen-producing male plant
of that species is nearby.
Bayberry and fragrant sumac walk the line between the two
groups. Usually they are dioecious, but sometimes one plant can
berry on its own.
When a top-selling species has separate male and female plants
and the buying public is interested in that shrub or tree for its
fruit, growers identify plants by sex. Holly bushes are commonly
tagged this way -- 'Blue Princess' and 'China Girl' are
berry-bearing females meant to be paired with compatible
pollen-producing males 'Blue Prince' and 'China Boy.'
It's not common to find male and female tags on less popular
dioecious species. Although many garden centers sell bayberry and a
fair number offer spicebush, only a few specialty nurseries might
have spicebush in the male variety 'Green Gold' and female 'Rubra,'
or female 'Myda' and male 'Myriman' bayberry.
To be sure to get fruit on spicebush, bayberry, and sumac, buy
only when they are blooming so you can look closely at the flowers.
You've found a male when the fresh flowers -- those that have
recently opened and show no signs of fading -- are producing
powdery pollen. If you do not find any pollen, chances are very
good you've found a female. One male is all you need to pollinate a
yard-full of females.
Dear Janet,
In November I put a bittersweet branch in water and am
keeping it in the house by a south window. Will it take root and
can I plant it outside next spring? I change the water every so
often and add a bit of liquid fertilizer. I've also found the
little seeds in the bittersweet and have tried to plant these but
it doesn't look like anything is coming up.
M.O.
Dear M.O.,
To grow bittersweet from a cutting, take a six- to twelve inch
hardwood cutting while the vine is dormant between November and
late March or a semi-hardwood cutting in midsummer.
Wrap and store hardwood cuttings like you would carrots, in a
moist 40 degree crisper drawer or buried outdoors in sand. In
March, re-cut the base of a hardwood cutting and "stick" it --
insert half its length into moist sandy potting mix. Then wait for
it to leaf out, grow it in good light, water it carefully, keep the
foliage from drying out and apply just a bit of dilute fertilizer.
Roots will begin to form after a month or two.
Stick more cuttings than you need because some will fail to
root.
Bittersweet is dioecious, having separate male and female
plants. So if you want the bright orange berries, grow two. Take
hardwood cuttings from a female -- one that had berries last fall.
Then at blooming time in June, identify a male so you can take
semi-hardwood cuttings from that one at midsummer. Stick
semi-hardwood cuttings right away.
Although you looked for berries and flowers as identifiers, take
cuttings from new branches that did not yet flower or fruit. These
usually root best.
The seeds will sprout in spring if you clean away the fruit,
plant them in moist potting mix, then set the planted pot or tray
in a refrigerator or outdoors. The seeds require two to three
months' chilling before germination time.
Short reports
Nightlights for poinsettias...
Paul Ecke, one of the leading names in U.S. poinsettia
production, writes in "The Poinsettia Manual" that a poinsettia's
show lasts longer if a small light is left burning near the plant
at night.
Green thumbs
up to retailers who keep gardening tools out
for the holiday shopping season. We gardeners love to give
practical gifts and prefer the real thing to gift certificates.
We're faithful to you all year when you cater to us during the
mis-labeled "off" season!
Green thumbs down
to snowbirds' covetous ways. Stop dreaming about growing
southern plants in northern landscapes. Those attractive trees and
shrubs you see during your winters down South are almost certainly
not hardy here or you would already be familiar with them.
Originally published 12/14/02