Climbing hydrangeas won’t bloom

I have had a climbing hydrangea for 4 years – but it has never bloomed. It is growing but does not produce any buds. It gets full sun and is in good soil. What can I do so it will produce blossoms?

I looked in a few books (including Trees and Shrubs for Pacific Northwest Gardens, 1990, by Grant and Grant) about climbing Hydrangea (Hydrangea anomala ssp. petiolaris) and they all said this vine is wonderful and robust but very slow to establish. You may just have to wait a few more years.

This hydrangea prefers a cool, moist root run so be sure to irrigate it in the summer and place a good mulch (such as compost or wood chips) a few inches deep. The mulch should not touch the trunk of the vine at the top of the soil around the vine. Established trees and shrubs don’t generally need feeding. Avoid using a fertilizer that is high in nitrogen, or it may add lush, green growth at the expense of flowers.

Here is additional information, from Virginia Cooperative Extension:
Excerpts:
“Climbing hydrangeas only bloom on vertical stems so vines growing on
the ground will not bloom. Minimal pruning is required. They bear lacecap inflorescences with an outer ring
of showy white sterile florets around creamy to yellow fertile flowers in late spring. Deadheading can be
done right after flowering to save energy and for aesthetics by cutting the inflorescences off above the first
leaf. Branches that extend out far from the climbing surface may also be pruned back in summer after
flowering to prevent the plants from being pulled from their structures by heavy winds, ice or snow.”
Reasons for lack of flowers on various species of Hydrangea:

Improper shearing and renewal pruning on H. macrophylla and serrata cultivars
Frost injury to early expanding growth buds
Pruning more than a month after bloom time in summer
Excessive shade
Excess nitrogen fertilization

Disease-resistant roses for the PNW

My neighbor wants a rose, but it will be planted in an organic
garden. It is a sunny warm spot (for Seattle), but I think disease
resistance is a must. What is a source for disease resistant roses
for our climate? Also, does growing clematis on a climbing rose limit its disease
resistance?

The reason that clematis and rose make good companions has to do with the
rose providing the structure the clematis needs, and the pairing allowing
for interesting combinations of color and shape, rather than one
providing disease resistance to the other.

Generally, the most disease-resistant roses are species roses, but there
are additional choices.

This list from Pacific Northwest Pest managment Handbook lists resistant roses.

This article from Washington State University Extension is entitled “Disease-Resistant Roses for the Puget Sound Area.”

There are several excellent books on growing roses in our area:

North Coast Roses : For the Maritime Northwest Gardener by Rhonda Massingham Hart (Seattle : Sasquatch Books, c1993)

Jackson & Perkins Beautiful Roses Made Easy : Northwestern Edition by Teri
Dunn & Ciscoe Morris. (Nashville, Tenn. : Cool Springs Press, 2004)

Roses for the Pacific Northwest by Christine Allen (Vancouver : Steller Press, 1999)

Roses for Washington and Oregon by Brad Jalbert, Laura Peters (Edmonton : Lone Pine Pub., 2003)

Roses for the Inland Northwest. Washington State University Extension ; [Washington, D.C.] : U.S. Dept. of Agriculture, [2004])

This book is a comprehensive guide to combining clematis and roses:
The Rose and the Clematis As Good Companions by John Howells ; photographs
by the author ; flower arrangements by Ola Howells (Woodbridge : Garden Art Press, 1996)

All of these titles are available in the Miller Library.

storing bare-root grave vines

I have purchased 150 grape vine, bare-root plants packed in damp wood shavings, covered by plastic. I have been storing them for about 1 1/2 weeks. A number of circumstances have prevented me from planting them and I am concerned they are going to begin to mold. The current weather forecast suggests I need to do something temporarily with them before permanent planting or I am going to lose, most if not all of them.

Any suggestions?

If at all possible you should place your plants in refrigeration or in the coolest place possible. Store them in the dark, and uncover the plastic. Check frequently to make sure the wood shavings stay barely damp.

Alternatively you can “heel them in” which means unpacking, but leaving the plants in bunches and temporarily “planting” them in either the ground or in large containers of peat moss based potting soil.

Source: Oregon Viticulture, ed. Hellman (2003).

Carex species and difference between grasses and sedges

I was looking at the Great Plant Picks list of recommended grasses, and I wonder why they exclude Carex, which I find is such a useful plant in the garden.

Great Plant Picks does in fact list two different Carex species but they are not on the list of grasses because Carex is a type of sedge, and sedges are not grasses. An article entitled “Sedges Have Edges” from Hilton Pond Center for Piedmont Natural History has a detailed explanation of the differences among grasses, sedges, and rushes. All three are graminoids, but grasses are in the Family Poaceae, sedges are Cyperaceae, and rushes are Juncaceae. According to the article, “a simple ‘touch test’ is the giveaway for sedges, whose stems when rotated have a very noticeable triangular shape–hence a total of three ‘edges.’ ”

Nanking cherry and cross-pollination

I have had a Nanking cherry bush that I planted 3 years ago. The first year, as I expected, it didn’t produce flowers or fruit. The second year, it produced some flowers and about 4 small green cherries, which disappeared off from the bush in about a week. This year, it had a lot of flowers, but only produced 2 small green cherries, which also disappeared in about a week. I only have the one bush, and it seems very healthy otherwise. Is it due to being so young still? Do I need a second plant? Any advice would be greatly appreciated.

According to the Arbor Day Foundation, Nanking cherry (Prunus tomentosa) “is not self-fertile. Two or more shrubs should be planted within 100′ of each other to ensure cross-pollination.”

Information from Alberta, Canada’s Agriculture and Rural Development website (no longer available online) has some suggestions on cross-pollination:

“Nanking cherries need cross pollination, for fruit production, therefore more than one plant is required, or an early flowering plum such as Brookgold, Bounty or Dandy. Mature plants reach heights of up to 2 m. Plant in rows 3 m apart with 2 m between the plants in the row. Prune annually to prevent shrubs from becoming too dense. Remove no more than one-third of the total number of branches at one time. This allows the plant to replace older wood with young, vigorous wood.”

There is a chapter on Nanking cherry in Lee Reich’s Uncommon Fruits Worthy of Attention (Timber Press, 2004) in which he states clearly that cross-pollination is needed (some information on the web says that it is self-fruitful…which might be true to a small extent, but you will have a much better crop with cross-pollination). Some key points: Nanking cherry does well in sun and well-drained soil. Full sun is preferable, but it will still bear fruit in a shadier spot. It grows vigorously, and can live 50+ years. “Annual pruning, though not a necessity, brings out the best in any Nanking cherry in terms of yield and fruit quality. Prune in late winter with the aim of keeping a bush open so that all branches are bathed in sun and quickly dried by breezes. Accomplish these goals by shortening some branches, removing others entirely, and leaving still others untouched. This pruning will also stimulate a steady supply of young, fruitful branches each year.”

loss of fragrance in roses

I wonder why my roses have lost their fragrance. My ‘Double Delight’ roses used to have a good smell, and now the flowers are bigger and there is no fragrance.

It does seem mysterious that a once-fragrant rose should lose all fragrance. There are many factors which might cause the perceived lack of scent. According to The Graham Stuart Thomas Rose Book (Timber Press, 1994), rose scent itself is complex, and is composed mainly of geraniol along with many other substances. It is mainly released from tiny cells on the surface of the petals: “Scent is produced mainly in the petals and is given forth when the growth of the flower and the atmospheric conditions are right. From this it will be seen why double roses have more volume of scent than singles […] scent is especially apparent in most flowers when the air is neither too cold nor too hot […] In extreme conditions, such as wilting, extra scent may be released […] Usually the best fragrance is obtained from a newly opened flower growing on a healthy, well-established plant on a windless day when growth is exuberant […] we may expect fragrance to be at its best on a day when the air is warm and moist rather than dry, when the plant will be functioning well. It is not that moist air conveys better than dry, but that the plant is giving it forth in greatest quantity.”

From the above, you may want to consider the following

When you discovered the rose had no scent, were the atmospheric conditions optimal for the release of scent?
If scent is most prominent on healthy plants, are there any underlying reasons (pests, diseases, cultural problems such as overwatering, poor soil, etc.) the plant might not be at its strongest?

Other things to consider:
Environmental pollutants affect not only our sense of smell, but the fragrance emitted by flowers, as this 2008 University of Virginia study describes:
“‘The scent molecules produced by flowers in a less polluted environment, such as in the 1800s, could travel for roughly 1,000 to 1,200 meters; but in today’s polluted environment downwind of major cities, they may travel only 200 to 300 meters,’ said Jose D. Fuentes, a professor of environmental sciences at the University of Virginia and a co-author of the study. ‘This makes it increasingly difficult for pollinators to locate the flowers.’

The result, potentially, is a vicious cycle where pollinators struggle to find enough food to sustain their populations, and populations of flowering plants, in turn, do not get pollinated sufficiently to proliferate and diversify.”

Another thing that you might ask is whether your rose was grafted, and perhaps you are getting a different rose coming up from the graft. The loss of fragrance and the different appearance of the flowers makes me wonder if this could be what is happening.

pruning and maintaining ferns

I have questions on general maintenance for the ferns in my garden. It is winter and the wood ferns (now about 4 feet in diameter) have fronds which are now partially brown. The deer ferns look similarly forlorn.
Should I prune all the old fronds off and let the new ones take over? How and when to do this without damaging emerging new growth?

Sources are divided on when and whether to prune wood ferns (Dryopteris). Some consider Dryopteris “self-cleaning,” meaning that the old fronds will eventually disintegrate on their own (Gardening with Woodland Plants by Karan Junker; Timber Press, 2007). If you are inclined to tidy up the look of your plants, they can be pruned of their old fronds after new growth begins in the spring (this can be risky: be careful not to cut the new fronds), or according to Pacific Northwest sources, in late February or early March before new growth starts. Rainyside Gardeners and Great Plant Picks, two Pacific Northwest resources, offer more information. Rainyside advocates pruning once there is new growth, and Great Plant Picks advocates pruning before new growth begins. The same is true for deer fern (Blechnum spicant, now renamed Struthiopteris spicant): “Old fronds should be cut back in late winter or early spring before new growth starts.”

This is a good general guide for pruning maintenance of ferns, written by Richie Steffen of the Hardy Fern Foundation. The first thing he points out is that cutting back ferns is purely an aesthetic choice; it is not necessary. If you do want to cut back, consider the type of fern: is it evergreen, winter-green, deciduous, or semi-evergreen? The answer to this question will determine the best practice.

Chamaecyparis pisifera and flagging

Chamaecyparis pisifera ‘Boulevard’ is prone to foliage
browning towards the interior of the tree as it matures. What is the
cause of this and is there any remedy?

I consulted Pacific Northwest Landscape IPM Manual (WSU, 2002), which
mentions that lower branches tend to die in older Chamaecyparis pisifera.
This resource mentions cedar flagging as one of the cultural or
environmental problems which may affect this tree. It is normal for
evergreens to shed some old foliage every year, but this may be
intensified by stresses like drought, recent or poor planting, root
disturbance, or hot wind. Symptoms show up in the form of browned
foliage, usually most noticeable in the fall. The current year’s foliage
stays green at the tips. Remedies for excessive flagging would include
close attention to irrigation during periods of summer drought,
preventing root disturbance, make sure the tree was not planted too
deeply, and improve drainage if the soil tends to stay wet. (Replant onto
a berm or raised bed, for example).

Since the browning you have observed is on the interior, flagging would
be a likely possibility. Typically, the dead foliage gets blown out of
the plant and the plant returns to normal growth in the spring.
The following link, to a discussion on University of British Columbia’s
Botanical Garden Forums, may be of interest to you.

If you think something else might be going on, such as Phytophthora, you
might want to bring photos and samples to a Master Gardener Clinic for
diagnosis. Signs of Phytophthora begin at the small roots, progressing to
larger roots. The inner bark will show a brownish color. Eventually, the
foliage will turn color (yellowish to bronze and finally brown). This
doesn’t sound like your description, however.

Apricots and other stone fruits for the Seattle area

I would like to grow some fruit trees on my property; we have room for maybe 2-3 small trees. Do you have any recommendations for the Seattle area? I’m partial to stone fruits — although I had heard that apricots (Prunus armeniaca) don’t do well in Seattle.

I don’t think you need to give up on the idea of apricots, as there are a few varieties that will do well here, such as ‘Puget Gold’ and ‘Harglow.’ The book, Fruits & Berries of the Pacific Northwest, by David Flaherty and Sue Elen Harvey, also mentions ‘Jannes’ and ‘Tilton’ for Western Washington. The book, Pacific Northwest Guide to Home Gardening, by Ray McNeilan and Micheline Ronningen, lists ‘Jannes’ and ‘Tilton,’ as well as ‘Moorpack,’ ‘Perfection,’ ‘Riland,’ and ‘Royal.’ I would also recommend that you look at the catalogs of several Washington State nurseries that specialize in fruit: Raintree Nursery, Cloud Mountain Farm, and Burnt Ridge Nursery. Since you mentioned small trees, you would probably be looking for dwarf forms, depending on the space you have available. These should also be available from the nurseries listed above.

pruning Euonymus shrubs

Is it possible to arborize a large Euonymus shrub (by
selectively pruning many of its branches to create a tree shape), as one
can with rhododendrons? I prefer pruning over removal, if that option is
available to me. What tips can you offer for pruning Euonymus in this
way?

It is a little difficult to offer advice without knowing which species of
Euonymus you are growing. There are many, some evergreen and some
deciduous. The pruning method varies according to the species. See the
link here, from Oregon State University, for information on some of the
different species.

If you would like to get back to me with information about the species, I
will be better able to assist you. For now, here is general
pruning information and links which may be of use.

Seattle gardening expert Cass Turnbull and the organization Plant Amnesty
offer helpful pruning hints. Excerpt:

Punch List for Tree-Likes. Take out:

Dead wood

Suckers from trunk, roots, or branches

Crossing/rubbing branches (the worst ones)

Branches hanging on the ground

Wrong-way branches

Too-far-up/too-far-down branches

Parallel branches

Head back to shorten (if necessary) on shrubs, not trees.

Tree-likes vary in the degree to which they may be thinned before they
sucker back or suffer dieback. Removal ranges from approximately
one-eighth to one-third total leaf area.

Another excerpt, on arborizing shrubs:

Other people strip up all the lower limbs of shrubs they consider too
big, making them somewhat reminiscent of lollipops or ostriches. I
hesitate to mention stripping because of these common abuses. However,
there are some instances where removing the lower limbs of a shrub is a
good option. It will depend on the type of plant and its location. Don’t
strip up plants just because they seem too big. Good candidates are ones
that are actually impeding foot traffic or totally obscuring windows. The
best subjects are non-suckering tree-like shrubs. Usually they are
broad-leafed evergreens, such as rhododendrons, pieris, camellias, or
strawberry trees (Arbutus unedo). Stripping up works best on very old
shrubs. By cutting off the lower branches you are “arborizing” them.
“Arbor” means tree, and you are turning your big shrub into a small tree.
English laurel is a good subject. Instead of a giant oppressive blob, you
can have an open, sort of oriental-looking, small tree. In fact, one
could say that most of these plants are trees in their native habitats.
They start out as shrubs and grow into understory trees in their
adulthood. We just expect them to stay in the shrub-like juvenile stage
forever.

Some shrubs can be arborized, meaning that they can be pruned into small
trees.

Pause before you strip, though. It’s a major step. Look inside your shrub
and evaluate how the trunk will look when it’s exposed. Is it fat? Good!
Does it lean and curve gracefully? Great! If possible, endeavor to leave
some branches lower down and inside to avoid the stripped or gutted
appearance. To alleviate the lollipop effect, thin out the upper canopy
of leaves, too. It should look a bit lacy and like a tree, not like a
solid ball. Don’t arborize more than a few plants in your landscape, it
begins to look silly if you do too many.

Be sure to leave enough leaves to collect sunshine in order to feed the
plant. Shrubs and trees vary from species to species in the degree to
which they will let you put them on a diet. Trees and shrubs which have
been starved by over thinning usually succumb to death in a drought or
freeze. Be sure to help heavily thinned, non-suckering plants by
supplying sufficient water and fertilizer.