grape vine producing uneven fruit sets

What causes some grapes to get to normal size and others to stay small? This is on a Concord vine about 7-8 years old.

Some varieties of grape produce naturally straggly clusters of fruit. According to The Grape Grower: A Guide to Organic Viticulture by Lon Rombough (Chelsea Green, 2002), Concord has a tendency to ripen unevenly in hot climates (such as the mid-South), but he doesn’t note straggly clusters as a characteristic of this variety. That makes me think the uneven size of your fruit is more to do with pollination. See the following, from Oregon State University Extension, which suggests that a cool, wet spell around the time of bloom can interfere with pollination and result in large numbers of unset berries. Rain, which also inhibits pollination, can also be a factor in poor fruit set.

There are other possible reasons for the uneven fruit set. If you are growing a variety of grape which is not ideally suited to your climate, or if the soil is overly rich or overly fertilized, you may not get abundant fruit.

on use of juniper berries for flavoring

Our microdistillery is going to be making gin. I’d like to know which species of juniper to use for the berries which will flavor it. Also, someone said that the berries were toxic. Is that true? Any other information about the use of juniper as a flavoring would be helpful, too.

Here is what Amy Stewart says about the use of juniper for gin in The Drunken Botanist (Algonquin Books, 2013):

“The juniper most widely is J. [Juniperus] communis communis, a small tree or shrub that can live up to two hundred years. They are dioecious, meaning that each tree is either male or female. The pollen from a male shrub can travel on the wind over a hundred miles to reach a female. Once pollinated, the berries–which are actually cones whose scales are so fleshy that they resemble the skin of a fruit–take two to three years to mature. Harvesting them is not easy: a single plant will hold berries in every stage of ripeness, so they have to be picked a few times a year.”

North Carolina State University’s Poisonous Plants database lists juniper as having low toxicity if consumed, and simultaneously describes the fleshy cones (“berries”) as both poisonous and edible, which I understand to mean that if you ingested large quantities of them it might be unwise, but there is a long tradition of using them for flavoring.

A 1998 article by J. Karchesy of the Department of Forest Products at Oregon State University discusses the uses of juniper for specialty products:
“The juniper berry oil of commerce is an essential oil produced by steam distillation of
Juniperus communis berries. This oil is composed mainly of monoterpenes, including
a-pinene, myrcene and sabinene as major components, lesser amounts of sesquiterpenes and
other volatile compounds. Commercial production is carried out in several European countries including Italy, France, Germany, and Austria. Perhaps the most famous use of this product is to flavor gin and alcoholic bitters. It is generally recognized as safe for human consumption (GRAS) and also finds use in many other food products such as frozen desserts, gelatins,puddings, and meats.”

encouraging Kalanchoe to bloom

Why do my house plants stop flowering after I bring them home? They are by a bright, sunny window. I bought Kalanchoe in 4 colors, and none flower any more.

Can you tell me if you feed the houseplants anything? Sometimes plants (indoors or outdoors) which are given a fertilizer that is high in nitrogen will produce a lot of leafy growth at the expense of flowers.

Make certain that you are providing ideal conditions for growing Kalanchoe. According to Barbara Pleasant’s The Complete Houseplant Survival Guide (Storey, 2005), Kalanchoe grown indoors needs bright direct sunlight, and warm temperatures (70-90 degrees) from late spring to early fall. In fall and winter, it requires 50-70 degrees. It should not receive any fertilizer from late winter to early spring, and in winter, let soil dry out between light waterings. More importantly, Kalanchoe responds to changes in its exposure to light, which is referred to as photoperiodism. Pleasant says that “before a kalanchoe will make buds, it must be exposed to a series of long, sunny days followed by at least 2 weeks of short days, less than 12 hours long. This is easy enough to accomplish by placing plants outside in summer and then bringing them indoors in late fall, just before nighttime temperatures drop below about 40 degrees. After you bring the plant in, keep it in a room where no lights used at night. When brought into bloom naturally, kalanchoes flower in January and February. To speed up the schedule, cover the plants with a box for 14 hours each night for 14 consecutive days. Blooms will appear about 6 weeks later. Snip off bloom-bearing branches after the flowers fade.”

pruning Ceanothus

How do I go about pruning Ceanothus?

My impression is that in general, Ceanothus should be pruned with a light touch. Portland gardening expert Ketzel Levine has some opinions on this topic:

“You can certainly prune Ceanothus but there is a bit of a trick. First of all never prune any stems that are larger than 1/4″ wide. Instead prune the very tips of each branch back to where you want it to be. And, since ceanothus bloom on ‘new’ wood, this should provide you with an even more spectacular show next year. Prune after the plants are through flowering; at that time you can also remove the spent flower spikes which will also help it look less wild.”

Ceanothus by David Fross and Dieter Wilken (Timber Press, 2006) says that “an annual trimming of the new growth will maintain a more compact form and improve the appearance of most species. The removal of spent flowers and fruit improves the vigor of many cultivars and will produce a tidier form. Taller species can be trained into small trees with early pruning, and the removal of interior dead wood as plants age produces a cleaner appearance. Once the arborescent character is achieved it is easily maintained and requires minimal effort. Shearing for hedges and formal effect is tolerated by most species if cutting into woody tissue is avoided. Prune immediately after flowering, and only back to the new year’s flush of growth.” The authors mention that although it requires a lot of work, there are some species which can also be trained as small hedges or as trellis plants.

Here is the Royal Horticultural Society’s guidance on pruning evergreen Ceanothus species: “Routine pruning is not essential and in fact are best not pruned. If grown as a bush, promote branching by pinch-pruning the soft tips on young plants in spring. Use secateurs to shorten over-long branches by up to a half in midsummer after flowering. Do not cut into older wood as the stumps may not regrow.”

invasiveness status of Alstroemeria in the PNW

I’ve just been given two pots of Alstroemeria psittacina ‘Variegata,’ a lovely red variety. Is this particular variety invasive here in the Pacific Northwest? I’ve grown the orange ones and then they took over–very hard to eradicate from beds. Does anyone know if the red ones are as invasive?

The Pacific Bulb Society lists this species under its previous name, Alstroemeria pulchella, and says it is weedy in some gardens and barely survives in others. Alstroemeria psittacina may be officially listed as invasive in some areas (in Australia, for example), but even if not officially designated as such, it may grow aggressively. This listing on the Floridata website, describes it as follows:

“This is a seductive plant. It is colorful, unusual, and exotic looking and effortless to grow once you get it going. Every gardener I know who has seen it has wanted it, begged a start, then nurtured it and delighted in it – for a few years. Then every one of them has come to curse the way it spreads and taken to ripping it out with a vengeance. Perhaps its best use is as breeding stock for developing more spectacular and less troublesome varieties of Alstroemeria.”

What you could do is grow your plants in a container, to avoid potential problems with weediness. I think aggressive spreading should be assumed with this genus unless otherwise specified.

diseases that affect the genus Arbutus

I was told by a local arborist that Arbutus ‘Marina’ in the area are all dying of some disease. I have 5 that were adversely affected or died over last winter but at the time I thought this was due to a cold winter. Is there a disease going around, or is it safe to get some new plants of this species and try again?

I know that the City of Seattle has listed Arbutus ‘Marina’ as an alternative to the disease-prone Arbutus menziesii, because it is supposedly less susceptible to the fungal and bacterial problems affecting our native madronas. However I imagine it is not immune, and perhaps what you have observed indicates that conditions for disease development were just right this year. You might want to talk to the city arborist and ask how the city’s plantings of this tree are doing. You could also talk to tree expert Arthur Lee Jacobson to see if he has any thoughts on this.

University of British Columbia Botanical Garden and University of Washington both have information about diseases that affect the genus Arbutus. A commercial operation, San Marcos Growers, comments on disease in Arbutus ‘Marina:’

“In the initial release of Arbutus ‘Marina’ the Saratoga Horticultural Foundation noted that the tree was a fairly pest free and disease resistant; we in fact started calling it the garden tolerant Madrone. Through years of growing and gardening with Arbutus ‘Marina’ we have discovered that it in fact has a few pests that feed upon it and a few diseases that can cause it harm. The new growth is occasionally attacked by aphids, which will cause the associated sooty mold. Ant control seems to be the best preventative for this. On occasion we also see Greenhouse thrip and soft scale. For these pests, the pest pressure on our garden plants have never reached a threshold that required us to treat with a pesticide. We treat our nursery plants as necessary to assure that they are pest free.

For many years we thought that Arbutus ‘Marina’ was resistant to plant diseases but in conditions that promote the disease we have found that Arbutus ‘Marina’ is susceptible to at least 2 plant pathogens. Phytophthora root rot is the most serious of these diseases but when planted correctly in well drained soils and not over irrigated this disease has not appeared to be a problem. In most cases we have seen this problem when the tree is being overwatered or has been planted too deep or in compacted soil. Unfortunately this disease seems to eventually kill the infected plant.

More recently we have seen several established trees losing lower leaves and small twigs inside the canopy. A laboratory analysis has proved this to be caused by the fungus Botryosphaeria. This fungus is opportunist in nature and usually only attacks plants that are under environmental stress of some form. A tree infected with Botryosphaeria may appear vigorous and healthy at its growth tips yet have twig die out within the canopy. The information for controlling this disease on ornamentals is limited but the general consensus is to reduce the stress to the plant and avoid wounding the plant unnecessarily. When pruning infected branches, do so well below all discolored wood and dispose of dead plant material. Clean pruning tools between cuts with a dilute solution of household bleach (1 part bleach to 9 parts water).”

snail and slug control

I have a big snail population in my yard. I don’t use pesticides and I want to avoid Sluggo or other iron phosphate type baits.

I have read online that decollate snails (Rumina decollata) eat brown garden snails (Helix aspersa). I’m thinking about ordering some of these as they say the decollate snails don’t eat your plants. Also I’ve read that garter snakes will eat the slugs and snails.

Decollate snails may not be imported into the Pacific Northwest. See this information from Oregon State University on nursery pests, excerpted here:
“Decollate snails, Rumina decollata, have been reared and released as biological control agents to control brown garden and other snails. They are native to the Mediterranean and have been in the US since the 1820s and in southern California since the 1950s. They are commercially available and have been used rather commonly in citrus orchards in California. They can harm native snails and are also plant feeders themselves. Decollate snails are prohibited from shipment to the Pacific Northwest but have managed to slip in at times.”

Oregon also lists Rumina decollata on its 2003 Invasive Species Report Card, and states that it is polyphagous, eating both plants and other snails:
“decollate snail, Rumina decollata (a polyphagous species that consumes both plant material and other snails, promoted as a biological control agent in areas heavily infested with European brown garden snail in California, reported for sale in a Eugene garden center in 2003)”

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) also states that decollate snails cannot be permitted across state lines:
“Decollate snails (Rumina decollata) and aquatic snails in the family Ampullaridae (e.g., Pomacea canaliculata, channeled apple snail), with one exception, may not be imported or moved interstate except for research purposes into an APHIS inspected containment facility.”

I’m not sure I’d recommend importing garter snakes, though there may be natives already in your garden or surrounding areas. See the Washington Department of Fish and Wildlife’s information about our native species, which includes tips for attracting snakes.

There are much easier methods than the above for controlling destructive snails. The same traps that work for slugs–beer in saucers, upturned melon rinds, or copper barriers around plants–should help. A vigilant eye will catch lots of them, too, and they can be squished if you aren’t squeamish. More information from University of California, Davis Integrated Pest Management is here.

I understand your reluctance to use iron phosphate products like Sluggo. Although it is certified as acceptable for organic use by the Organic Materials Review Institute (OMRI), information published on the website of Oregon State University in May 2013 quotes recent research suggesting that even “less toxic” iron phosphate slug bait can cause iron toxicosis, and should be kept away from animals and children. Here is a fact sheet from the National Pesticide Information Center which explains the risks. Stormwater runoff may also be a concern, although one typically doesn’t use much of the stuff at a time. You might borrow a duck or two to come in and do some serious snail-eating!

pruning Thujopsis

I’m looking for resources on proper pruning or rejuvenation for Thujopsis. We have a 50-60 year old specimen.

According to Michael Dirr (in Dirr’s Hardy Trees and Shrubs: an Illustrated Encyclopedia), Thujopsis dolabrata is “too beautiful to mutilate with pruning shears.” This website of a Seattle-area gardener suggests that you may be able to prune it lightly by candling the leader.

According to George Brown’s The Pruning of Trees, Shrubs and Conifers (Timber Press, 2004), specimens of this tree vary widely in habit. Some form a definite leader, while others are “untidy, spreading shrubs. Of those which grow out of this shrubby habit, a number produce rival leaders and the result is a small tree made up of slender upright trunks with their supporting branches.” If your tree has multiple leaders, it is probably too late to prune them–this kind of pruning would be done on a younger tree.

I spoke with a docent at Seattle’s Japanese Garden, which has Thujopsis, and she said that they are not pruned, except to remove dead, damaged, or diseased branches. You may find this general information on pruning conifers from Brooklyn Botanic Garden useful.
Excerpt:
“As with any plant, dead or diseased conifer branches should be removed immediately, regardless of the time of year. Any other pruning should be done when the plant is dormant. Unlike many deciduous shrubs, most conifers can’t re-sprout from older wood (yew, arborvitae and podocarpus are exceptions), and so a good rule of thumb is never to remove more than one-third of the total growth at a time. If you prune too drastically, the plant may never fully recover. Many of the dwarf varieties never need to be pruned, but do appreciate some thinning to allow air and sunlight to penetrate to the interior of the plant.

The most common method of pruning evergreens is known as ‘cutting’ or ‘heading’ back. Only part of the branch is pruned; the terminal or tip growth is trimmed to side or lateral buds or branches. This promotes thicker, more compact foliage and a smaller overall plant.”

It sounds as if you should do the bare minimum in terms of pruning. If you really need to reduce the tree’s size, it would be wise to consult a certified arborist.

best time to plant conifers

The nursery recommended waiting to plant a Cedrus deodara until after the first hard frost. As we are in USDA Zone 7 (the lower limit for a deodar), I’d think we would want to get it in the ground as early as possible. Any idea what the rationale is behind this advice?

I am really not sure what their rationale might be. I agree with you that planting in the fall is preferable. Here is information which supports this:

Excerpt from Brooklyn Botanic Garden booklet on conifers:

“Across most of the country, spring (early or late, depending on how far north you are) and early fall, when temperatures are cooler and rainfall more abundant, are the best times to plant conifers. To reduce transpiration or water loss from the tree, plant on an overcast day when there is ample soil moisture.”

I don’t know if your tree was a bare-root specimen or container-grown. Here is what Keith Rushforth says in his book Conifers (Christopher Helm, 1987):

“Bare-rooted stock can only be planted during the dormant season. This restricts planting to the period November to April. Planting during midwinter is better avoided, because cold, dry winds during the winter can desiccate the young plants before the roots have been able to make new growth. Planting after April is only feasible if the plants have been held dormant in a cold store.

Container-grown stock can be planted out during most of the year, although the period of maximum growth from late May to early August is better avoided unless watering is no problem. A check should be kept on whether winter-planted stock needs watering; it is very easy for the compost to dry out during dry periods in the winter.”

Based on the above, it seems like a good idea to plant now (fall).

transplanting and caring for Iochroma australe

I grew from a seed from Kew Acnistus australis, now known as Iochroma australis. It is a small tree with white trumpet blooms. It is 8 years old and lives in the shade between two houses. I need to move it. Can you suggest methods for transplanting successfully? Also, any other information you might have about this plant would be great.

The current name of your plant is Iochroma australe, and it is in the Solanaceae family.

Is this tree hardy for you? Sunset Western Garden Book (2007) indicates that other species of Iochroma are not frost-hardy. Iochroma takes full sun to part shade, and requires regular watering. It is not a common plant in our area, and information about it is scarce. There is a reference to it in an article called “Get the Wows!” by Brian Minter in the October 2002 issue of Gardens West, where it is mentioned as an unusual container plant which is brought to a location under an overhang for the winter (in British Columbia). Iochroma is also featured in an article by Julian M.H. Shaw (pages 154-192) in the September 1998 issue of The New Plantsman (published by the Royal Horticultural Society). The name Iochroma comes from Greek for violet-colored. Since your plant has white blooms, it is probably a cultivar. There is one called ‘Andean Snow’ which has white blooms and is mentioned in the New Plantsman article. It grows “in a sheltered bay about four metres from the nearest wall,” and is hardy in Nottingham, England.

Fall is often a good time for moving trees and shrubs. Be sure to get as much of the root system as you can when moving your Iochroma. I am assuming you are moving it to a sunnier spot, possibly one with some shelter from fall rains and winter cold. The Royal Horticultural Society has helpful information about how to move mature trees and shrubs.