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Plant Answer Line Question

Keywords: Mexican plants, Plant care, Deppea

I have a plant, Deppea splendens, purchased through a special offer from Pacific Horticulture. It is a native of Mexico. This year (I've had it for about 2 years) it looks very healthy and has gotten quite a bit bigger. It is supposed to flower, but it has yet to do so for me. Any answers?


Deppea splendens is such a rare (previously almost extinct) plant that none of our standard sources have any cultural information. However, there was an article written about it in the April 2000 issue of Pacific Horticulture by Kathy Musial which mentions that it needs a frost-protected spot if it is to flower. The article recommends growing it in a container in colder regions so it may be brought into a sheltered area. Overly dry conditions will also cause the flowers to abort.

Excerpts from the article are included in University of British Columbia Botanical Garden's "Botany Photo of the Day" web page.

Date 2018-10-10
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Plant Answer Line Question

Keywords: Plant care, Zamioculcas, Palms

What are the cultural requirements for Zamioculcas?


Zamioculcas is in the plant family Araceae, and its common name is the Aroid palm. According to the Sunset Western Garden Book (2007), this tropical African perennial which resembles a cycad or a palm will grow slowly to 4-5 feet high by 3-4 feet wide. Grown outdoors, it prefers partial to full shade, but indoors you should provide bright filtered light. It should be placed on a tray of moistened pebbles, and misted occasionally. During active growth, keep the soil evenly moist, and give it balanced fertilizer once a month. During the fall and winter months, do not fertilize, and only water when the top inch of soil becomes dry. In summer, the plant may be moved outside to a shady spot. All parts of this plant are poisonous.

You can find discussion among growers of Zamioculcas zamiifolia (sometimes called "the ZZ plant") on the University of British Columbia Botanical Garden Forum.

Date 2018-04-21
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Plant Answer Line Question

Keywords: Plant care, Hydrangea

I am attempting to find detailed plant information on a variety of hydrangea called Hydrangea macrophylla 'Miss Belgium', and can find very little in my plant books and online. Do you have any suggestions? Some of the details I am looking for are flower shape and size, plant habit, height & spread, and foliage details.


I found some information about Hydrangea macrophylla 'Miss Belgium' in Glyn Church's book, Hydrangeas (Cassell, 1999):

An excellent pink in alkaline soil or in containers. The plant is ideally suited to pot and tub culture as it stays small and compact (3 ft.) and the rounded heads tend to be tiny, keeping the flowers in proportion to the bush. Its free-flowering habit and healthy nature are its good qualities. It is not the best plant for acid soils as the flowers will be a strident purple-blue.

There is a photograph of 'Miss Belgium' in Corinne Mallet's Hydrangeas: Species and Cultivars (vol .1).

Heritage Hydrangeas' website has this description: "Bright magenta-red on neutral soils or purplish blue on acidic soils, the centre of each floret is always white. Impressive flowers on a compact shrub."

Date 2018-06-14
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Plant Answer Line Question

Keywords: Plant care, Leycesteria

I am trying to find the proper soil pH for growing Leycesteria 'Red Shuttle'. I am hoping to plant it in partial shade next to rhododendrons (acidic soil). How will it do?


Leycesteria 'Red Shuttle' is the formosa species and should do well in any fertile soil, provided it is not highly alkaline (according to The Plant Care Manual by Stefan Buczacki (Crown Publishers, 1993).

Plants That Merit Attention, Vol. 2, Shrubs , (by the Garden Club of America, 1984, p. 172) states:

Needs sun for best bract and fruit color; prefers rich, moist loam; tolerates wind, drought, and air pollution...A handsome woodland shrub best in natural setting or shrub border. Needs sun for best flower and fruit color. May be pruned in spring. Partial dieback in winter not unusual; shrub rejuvenates the following growing season, often growing back successfully from roots....

Trees and Shrubs for Pacific Northwest Gardens (by J. Grant, 1990, p. 239) states:

...This shrub is easily grown in any good garden soil in full sun but prefers a rich, moist loam. It may achieve a height of as much as 15 ft. in a sheltered position. The rootstock is perfectly hardy, but the top is occasionally cut to the ground in exceptionally severe winters. If pruned almost to the ground every year, which is one method of treatment, it will send up lusty 6-ft. shoots and flower freely during the latter part of the summer....

Date 2019-02-20
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Plant Answer Line Question

Keywords: Lysimachia, Plant care, Growth

I bought a Lysimachia punctata 'Alexander' (variegated) at a plant sale last weekend. I can't find anything about it in my books. Can you tell me more about it? How tall, invasive or not, best place to plant, anything else you think I should know.


I found information on the website of a local gardener, Paghat, with a detailed description of this form of loosestrife. Although it is not supposed to be as aggressive as the species (L. punctata) or as invasive as L. vulgaris (a noxious weed in King County), I recommend keeping an eye on it. Paghat says:
"'Alexander' has variegated leaves, sage-green with cream borders, and sunny yellow flowers. It purports to be a more restrained version of a flower that in the species form is notoriously invasive and often too aggressive for neighboring perennials. Even 'Alexander,' though comparatively slow growing, eventually becomes a large two-foot by two-foot clump with a big root system that can threaten nearby delicate flowers, so take care what you plant around it."

Date 2018-08-23
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Plant Answer Line Question

Keywords: Plant care, Jasminum

I have a question about the common jasmine plant. Can it be planted in a pot and left on the patio all year round? It will be attached to a fixed trellis. What should we do to protect the plant in the winter?

We live in Langley BC, so our weather is quite similar to yours.


The American Horticulture Society's A to Z Plant Encyclopedia reports that Common Jasmine (Jasminum officinale) is only hardy to zone 9. (Seattle is zone 8, Langley may be a touch cooler)

However, local author (I believe she lives in BC) Christine Allen reports that Jasminum officinale, also known as poet's jasmine, is hardy in our climate if protected from cold, drying winter winds. I think if you move your pot against a wall out of the wind you should be ok.

Date 2019-02-20
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Plant Answer Line Question

Keywords: Persea, Plant care, Indoor gardening

We have a large avocado plant (indoors) that is mystifying us. A couple months ago, it shed most of its leaves. The leaf would get droopy and the tips of the leaves would turn brown and dry out and then spread up the leaf. It got down to its last seven leaves and then seemed to stop, although all of these leaves have varying degrees of this leaf tip burn. Now over the last month or more, small new growth is appearing. They have not grown much at all and are only about an eighth of an inch long.


When growing an avocado (Persea species) indoors, you will need to be sure it is getting enough light. It is normal for the plant to drop older leaves. You should also keep the plant in a cool spot. According to The Houseplant Expert by D. G. Hessayon (Expert Books, 2001), your plant will do best if you repot it annually and pinch the tips to encourage bushy growth. Lee Reich discusses growing avocados indoors in an article for California Rare Fruit Growers. Here is an excerpt:

"Indoors, avocado plants are often gangly and sparse with leaves. One reason for the plant's gawky appearance indoors is light. Lack of sufficient light causes stems to stretch for it. Another reason is that avocados shed many buds along their stems, buds that might have grown into side branches. The result is a plant stretching out for light, sending out new growth mostly from the tips of the branches and shedding old leaves.
There are several things indoor gardeners can do to keep their plants more attractive. Most obvious is to give an avocado tree bright light. Also, the stretch for light is exaggerated when warmth stimulates growth, so the ideal spot for the plant is at the brightest window in the coolest room. Beyond that pruning back a stem or pinching out its growing tip stimulates branching by awaking dormant buds (not all are shed) further down the stem. There is nothing that can be done about the shedding of older leaves."

Grown outdoors in an agricultural setting, avocado plants sometimes get leaf tip burn from salt accumulation, as this article from California Rare Fruit Growers explains. If you are using especially salty tap water or overfertilizing your plant, that might be causing the burnt leaf tips. Other causes could be lack of water, too frequent light watering, or poorly draining soil.

Date 2018-10-20
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Plant Answer Line Question

Keywords: Persea, Plant care, Avocado

We know avocados like dry soil, but are there specific guidelines to follow?


"Growing conditions: Give avocado direct light; insufficient light will cause spindly growth. Provide a warm temperature and medium humidity. Keep the soil evenly moist but not wet and soggy. Fertilize once a month throughout the year... Use an all-purpose soil mix for repotting... Avocado is vulnerable to aphids, mealybugs, scale insects and thrips."
Source: The Time-Life Gardener's Guide; Foliage Houseplants, 1988, p. 125

"Growth habit: The avocado is a dense, evergreen tree, shedding many leaves in early spring. Growth is in frequent flushes during warm weather in southern regions with only one long flush per year in cooler areas."

"Foliage: Avocado leaves normally remain on the tree for 2 to 3 years."
Source: California Rare Fruit Growers Association website

Date 2018-04-05
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Plant Answer Line Question

Keywords: Capsicum, Plant care

For the past several years, I have tried to grow green peppers in our garden. The problem I have had is that they never grow very big, and the peppers never get much bigger than a small plum. I fertilize my garden, add compost, but still get small peppers.


Peppers are tricky in our climate. Quoting from Growing Vegetables West of the Cascades by Steve Solomon: These heat-loving plants do not readily adapt to climatic conditions north of the Yoncalla Valley..they are often irreversibly shocked by outdoor night-time temperatures below 55 F.Many gardeners make the mistake of setting peppers out at the same time as tomatoes right after there is no frost danger. This, however, will almost certainly expose them to overnight temperatures of 45 F or even worse. Any surprisingly cool night during June can shock peppers sufficiently to stop their growth for a time. North of Longview, Washington, and along the coast, only the hardiest pepper varieties will grow in cloches or greenhouses.
Source: Growing Vegetables West of the Cascades, by S. Solomon, 2000, p. 210, 236.

Oregon State University has an article entitled "Spice Up Your Garden with the Perfect Pepper" with a link to a guide to growing peppers in the Northwest.

Date 2018-04-05
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Plant Answer Line Question

Keywords: Plant care, Narcissus

I'm having a problem with my daffodils. They came up, but very few of them are blooming. This is the third year for them, and the worst turn out. They seem to be turning yellow at the bottom of the plant. They have multiplied well, and came up looking fine. Several of my friends are having the same problem. Could it be because they had so many days of below freezing weather this winter?


We found a helpful article from the American Daffodil Society. Potential causes for a lack of flowers include lack of fertilizer, too much nitrogen fertilizer, shade, competition with other plants, poor drainage, virus, foliage cut off too soon, need to be divided, or weather stress (such as early extreme heat) in the spring.

The cold weather should not have been a problem provided the bulbs were planted deep enough.

Date 2018-07-13
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Plant Answer Line Question

Keywords: Schizachyrium, Plant care, Transplanting, Ornamental grasses

Schizachyrium scoparium seems to me to be difficult to transplant. They die on me when moved. What could I be doing wrong? The time of year? Adequately watered?


According to the Color Encyclopedia of Ornamental Grasses, Schizachyrium scoparium requires full sun, prefers good drainage or sloping ground. Does not persist on highly fertile soils or in excessively moist conditions, and suffers if the crowns are crowded by mulch.

Propagate by seed or by division in spring.

Grasses are sensitive to soil level, especially when young. Ideally, the crown of the grass should sit just slightly above the soil surface. Planting too low can rot grasses and planting to high can cause them to dry out and die.

Mulch of all sorts can be an efficient method of controlling weeds and conserving soil moisture. Many species, such as Schizachyrium scoparium, cannot tolerate having mulch pushed up around their crowns, a practice that often promotes rot and disease at the base of the plant.

Source: Color Encyclopedia of Ornamental Grasses, by R. Darke, 1999, pp. 121, 276.

Date 2017-12-09
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Plant Answer Line Question

Keywords: Ixia, Plant care

I am very interested in corn lilies growing in the Seattle area, and I would like to know how to grow them and where to find some.


At this time of the year, corn lilies (Ixia) have already done their flowering, and I do not know of any place to send you to see them.

Regarding how to grow these bulbs, the following is quoted from Sunset Garden Book (2001), pp. 406-407:

African Corn Lily:
Clump of narrow, almost grasslike leaves sends up wiry, 18-20 inch stems topped by short spikes of 2 inch flowers in late spring. Each six-petaled blossom opens out nearly flat in full sun but remains cup-shaped or closed on overcast days. Colors include cream, yellow, red, orange, and pink, typically with dark centers. Most Ixias sold are hybrids of the South African species Ixia maculata.

Grow in well-drained soil. Where winter lows usually stay above 20 degrees F, plant corms in early fall, setting them 2 inches deep and about 3 inches apart. ... Let soil go dry when foliage yellows after bloom. Where corms will not be subject to rainfall or irrigation during dormant period, they can be left undisturbed until the planting becomes crowded or flowering declines. When this occurs, dig corms in summer and store as for gladiolus until recommended planting time in your area (the nursery can tell you this). Where corms will receive summer moisture, dig and store them after foliage dies back; or treat as annuals. Potted corms (planted close together and about 1 inch deep) can be stored in pots of dry soil.

Date 2017-12-09
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Plant Answer Line Question

Keywords: Plant care, Coleus, Medicinal plants

I want to know about Coleus forskohlii a plant of South Africa. What growing conditions does it need, and what are its medicinal properties?


The plant you ask about is Coleus forskohlii (also known as Plectranthus forskohlii) in the family of plants called Lamiaceae. If your growing conditions resemble those of its native range (it grows wild in parts of West Bengal), you may be able to grow this plant.

The article referenced below, entitled "Development of Coleus forskohlii as a medicinal crop", from the Food and Agriculture Organization Document Repository, should give you much information of interest. The document may be found in the online FAO Corporate Document Repository.

Here is an excerpt from the above web document:
Coleus forskohlii grows wild on sun-exposed arid and semi-arid hill slopes of the Himalayas from Simla eastward to Sikkim and Bhutan, Deccan Plateau, Eastern Ghats, Eastern Plateau and rainshadow regions of the Western Ghats in India. Latitudinal and altitudinal range for the occurrence of the species is between 8 degrees and 31 degrees N and 600-800 m respectively. The species was studied for its ecological preferences in its native habitats throughout its distribution range excluding Eastern Plateau, Sikkim and Bhutan. Before the botanical studies were undertaken, the species was studied in the regional floras and herbarium specimens were examined in seven zonal herbaria of the botanical survey of India at Dehra Dun (Himalayan flora), Allahabad (Central India flora), Shillong (northeastern India flora), Jodhpur (Rajasthan flora), Pune (western India flora), Coimbatore (southern India flora) and Port Blair (Andaman and Nicobar group of islands flora), as well as at the Forest Research Institute, Dehra Dun and the Blatter Herbarium in Bombay. Eleven representative ecogeographic areas were selected for habitat and population studies; between 1982 and 1985, 27 botanical trips were made for the purpose. Coleus-growing areas in the Himalayas in Uttar Pradesh were visited every month from April to December, and the other areas were visited at least twice during the blooming period. The following is the summary of the observations made on different populations and habitats of C. forskohlii (Shah 1989).
C. forskohlii is a subtropical and warm temperate species naturally growing at 600-1800 m elevation
The species grows on sun-exposed hill slopes and plateaus in arid and semi-arid climatic zones
The species inhabits loamy or sandy-loam soil with 6.4 to 7.9 pH
The species is herbaceous with annual stems and perennial rootstock

The medicinal uses of this plant have not been evaluated fully for safety. Sloan-Kettering Cancer Center also has useful information about Coleus forskohlii. Here is a brief excerpt: "Very limited data are available concerning the efficacy of forskolin. Most studies performed with forskolin have been human trials; those performed on heart failure and glaucoma are inconclusive."

As with any drug or herbal medicine, you should consult a medical professional if you have questions about its use.

Date 2018-04-11
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Plant Answer Line Question

Keywords: Plant care, Malus, Plant diseases

I am looking for a Malus (crabapple), not necessarily native, but is decorative in terms of blooms and foliage. I am also interested in plant diseases. I am hoping for a tree that will mature to about 20 feet with a 20 foot spread. Growing conditions are half shade, half sun, behind a semi-dense fence. We live in the San Juan Islands where the soil is not great and the tree will not get much water past establishment.


Here is what I found about the culture of flowering crabapples from the book Flowering Crabapples, the Genus Malus, by Fr. John L. Fiala (1994), p. 45:

"Crabapple trees luxuriate in full sunlight in deep rich soils that are well drained. Soils with a pH range of 5.0 to 7.5 suit crabapples well, but the ideal pH range is from 5.5 to 6.5. Even if gardeners are fortunate to have ideal soil conditions, they may not be able to allocate the best part of the garden to crabapples. Flowering crabapples, however, are not greedy and will accept almost any soil that is not waterlogged or overly dry. As long as the soil has a reasonable amount of nutrients and water, crabapples manage to do very well.

"Like most plants, crabapples prefer rich sandy loams, but even in heavier clay soils they do better than many other trees and shrubs and seem to bloom well once they are established. They will accept slightly wetter soils than lilacs, for example, but in these heavier soils they should have excellent drainage as they will not grow in waterlogged, swampy areas nor in soils inundated for long periods of time."

Regarding particular trees you might like that would be disease-free, I found a couple of crabapples that were listed in The Pacific Northwest Gardener's Book of Lists,by Ray and Jan McNeilan (1997). This is from page 24:

1. Malus 'Prairiefire' has red foliage when young that matures to deep green, has bright pink/red blossoms and deep purple-red fruit. It grows to 20 ft x 20 ft and has excellent resistance to scab and mildew (Pacific NW scourges).

2. From the book Flowering Crabapples, the Genus Malus, by Fr. John L. Fiala (1994), p. 147: Malus sieboldii 'Calocarpa' (trade name, Redbud crabapple) is a dense, upright to spreading tree, 15 ft high and as wide... buds deep red, opening to single, white to pink-white flowers 1.4 in across; fruit 0.4 in diameter, bright red to red-orange... A reliable, abundant, annual bloomer... One of the most beautiful of all the ornamental crabapples both in bloom and in fruit. Birds relish the small fruit which never is messy.
From The Pacific Northwest Gardener's Book of Lists, p. 25, I found that this tree is rated 'excellent' in terms of resistance to both mildew and scab.

3. Malus 'Strawberry Parfait' is a "vase-shaped, spreading tree 18 ft high and 20 ft wide; leaves red-purple, turning green with maturity; buds red, opening to single, pink flowers in clusters; fruit yellow with red blush, 0.4 inch in diameter. Excellent disease rating but not rated for fire blight [bacterial disease]. Not very ornamental."
From The Pacific Northwest Gardener's Book of Lists, p. 25, I found that this tree is rated 'excellent' in terms of resistance to both mildew and scab.

[Note: fire blight appears to be more the issue in the midwest and eastern U.S.]

Date 2017-12-09
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Plant Answer Line Question

Keywords: Plant care, Vegetable gardening, Herbs

What herbs and vegetables grow well in very little sun?


The following is a list of vegetables that can tolerate partial shade. While productions may be greater in the sun, these plants will produce an edible crop when grown in a shady location.

From an article on The Old House Web (no longer available online):

Brussels sprouts
Salad Burnet
Summer Squash

Lemon Balm

This article ("Best Shade-Tolerant Vegetables") in Mother Earth News offers more detail about the amount of sun or shade needed.

Remember that most of these plants do not grow in complete shade. Plants will need some morning, evening or filtered sun; a total of two to six hours of direct sun is the minimum.

Date 2018-09-12
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Plant Answer Line Question

Keywords: Echeveria, Plant care

I have a start from a large hen & chicks (Echeveria). I have seen these plants grow up to 6 feet tall like a shrub. My start is over two years old. It takes off and seems to thrive, but never gets tall or hardy. It seems to go a year and then the outer leaves wilt. Once it got big enough to tip over, so I am wondering how to give it the right pot and correct soil to allow it to grow. It is located in our west sun room here in the great northwest. Is it alright outdoors in the summer?


I wonder if you have information about the particular species of Echeveria you are growing. Usually, 'hens and chicks' is the common name for Echeveria glauca. The larger growing Echeveria are the ones with "loose, cabbage-like rosettes which reach a foot or more in diameter on heavy stems" (from The Book of Cacti and Other Succulents by Claude Chidamian, Timber Press, 1984).

I consulted Victor Graham's book, Growing Succulent Plants (Timber Press, 1987) for some general guidelines on the best growing practices for Echeveria. He says that the soil you provide should be gritty and on the poor side (for good drainage), and they should not be overfed. In The Succulent Garden: A Practical Gardening Guide by Yvonne Cave (Timber Press, 1997), the recommendation for areas with wet winters such as ours is to grow them in containers on a covered porch or in any sunny spot with overhead cover. In the warmer, drier months they can be placed or planted in the garden without cover. Your sun room sounds like a fine place to grow them during the winter here, although they may prefer morning sunlight and afternoon shade to bring out the best color in their leaves.

The Brooklyn Botanic Garden has a page on growing succulents that may be useful.

Date 2018-08-15
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Garden Tip

Keywords: Plant care, Plant diseases--Control, Insect pests--Control, Attracting wildlife

By November Seattle has usually had a good hard frost and most of our herbaceous (non-woody) perennials have either turned to mush or look a bit tattered. Before you give in to the temptation to cut back everything in sight, consider the advice of natural gardening advocates James Van Sweden, author of Gardening with Nature (Random House, 1997) and Jackie Bennett, author of The Wildlife Garden (David & Charles, 1993):

  • Leaving seed heads and dead stems over the winter gives the garden winter interest, especially if we get some snow
  • Seed heads from Black Eyed Susans, Echinacea, Larkspur and Evening primrose provide bird food
  • Beneficial insects hibernate or over-winter as eggs on plant waste
  • Marginally hardy plants like some salvias and lavenders benefit from the little bit of frost protection from the desiccated stems

On the other hand, sanitation is critical if your apples suffered from codling moth or scab or your roses suffered from black spot. Rake up and dispose of every single diseased leaf or infected fruit. Insect and disease organisms also over-winter on plant debris, so if you had a problem this year, start the treatment now with a thorough clean-up.

Date: 2007-03-26
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