Plant Answer Line questions and answers.
Does the Opuntia fragilis in the Puget Sound carry a vernacular name of dune or shore prickly pear?
The most common vernacular name of the cactus Opuntia fragilis in Washington is brittle prickly pear. When I searched for dune or shore prickly pear, I found these common names connected with other species of Opuntia.
For more information about Opuntia fragilis, see the Washington Flora Checklist and the USDA Plant Profile.
My Sky Rocket junipers are declining. To me it looks like mite damage accompanied by winter damage. The top of the plant is still healthy looking. There are spider mites present. It does not resemble phomopsis, but could be phytophthora. Please let me know what you think.
I checked Diseases of Trees & Shrubs by Sinclair, Lyon and Johnson and Juniper virginiana does not get phytophthora (or at lease this good authority does not list that disease.) It does list a number of other diseases including blight, canker, phomopsis, among many others.
The HortSense website of WSU Cooperative Extension mentions Juniper webworm, which creates heavy webbing, which could resemble mite webbing.
Of course it could be winter damage, like you guess or nitrogen deficiency if the Ph is high (near a lot of concrete?), or salt damage (from melting ice in past winters?).
You should take a sample in to a Master Gardener clinic. If they do not know the cause, you can ask that they “submit it to the diagnostic center at the Center for Urban Horticulture.”
Locate a Master Gardener Clinic within King County at this website.
I have two pumpkins that I grew. One is 5 lbs. and the other is 8.5 lbs. They are only orange on the the side that was on the ground. I have already picked them as the vines were dying back. Will they ripen more? And how will I know when they are ripe? I have them in the garage. I want to use them to make pies.
I found the following on the web page of Pumpkin Nook, a commercial site.
Extending the season- If your pumpkins are still on the vine, they are best left there. Cut away any leaves that may block the sun, however small. In the waning hours of daylight, the fruit can use every ray it can get. If Jack Frost is about to stop by, get some large plastic sheeting. Cover the fruit and the vine. Anchor the plastic with bricks or rocks to keep the wind from blowing it off. If the next day is going to be very cold, you can leave it on all day. If not, remove it.
Ripening out of the patch- As previously mentioned, green and partially orange pumpkins will ripen up with sunlight, warmth, and time. Just follow these steps:
Here is more information (now archived), from the University of Illinois Extension.
I am trying to plant some bulbs but they are being disturbed and eaten by the squirrels. Do you have any tips and tricks to protect my bulbs from being snacked on?
Here is a 2009 article by Sally Ferguson in the online archive of BC Living magazine on preventing squirrel snacking:
Excerpt:
Q. How do I keep squirrels from digging up bulbs?
A. Squirrels can be terrible pests! They won’t bother daffodils and other narcissi bulbs (which taste terrible to them!), but they find tulips and crocus in particular to be worth the effort to sniff out and dig up.
The only sure-fire way to protect tulips and crocuses and other tasty bulb treats from squirrels is to lay wire mesh such as chicken wire on top of the bed. The squirrels can’t dig through the mesh and the flowers will grow neatly through the holes.
Bulbs are most vulnerable in fall immediately after planting when the soil is still soft and worked up. Digging then is easy! Squirrels often “chance” upon bulbs when burying their nuts in soft ground. Or they are attracted by “planting debris” such as bits of papery bulb tunics and other bulb-scented bits from the bulb bags. Don’t advertise your plantings: clean up and keep those squirrels guessing!
Here’s one neat trick that garden writer Judy Glattstein has found to work: after planting new areas, lay old window screens in frames on the ground, covering the newly-worked up soil. The screen weighs enough to
foil the squirrel, but allows for air circulation and rainfall. Once the ground has settled, remove the screens and store for future use.
Another remedy that some find successful is to feed the squirrels during the fall and winter. The theory is that the local squirrel population, when offered a handy plate of peanuts or other easy-to-get treats will leave your bulbs alone. At the White House, the gardeners put up six peanut-filled feeding boxes to satiate the furry denizens there — and reduced squirrel damage on bulb beds by 95 percent!
Many gardeners claim success with commercial repellents, but these are often sticky and unpleasant to deal with, or wash away in the rain.
Home remedies include sowing cayenne pepper into the soil or on the bulbs before planting and scattering moth ball flakes on the ground. You will find advocates and detractors of both methods. A favorite Dutch remedy is
to interplant Fritillaria imperialis. This tall dramatic plant gives off an odor that squirrels (and deer too, reportedly) find repellent. There is a book on the subject, Outwitting Squirrels, by Bill Adler, Jr. (1988 Chicago Review Press, Chicago, IL). It’s aimed at owners of bird feeders, but you may find some helpful hints.
I have a tree peony that started as a seedling from a plant of a friend gave me 8-10 years ago. I would like to try to propagate mine from seed. From the little I’ve read, it seems this is a difficult process. Can you help me?
I believe you are correct that propagating tree peonies from seed may be a little challenging. It can be done, but home gardeners may find it easier to propagate by grafting, which is described by a link at the end of this answer.
The American Horticultural Society’s Plant Propagation, edited by Alan Toogood (DK Publishing, 1999) rates seed propagation of deciduous tree peonies as moderate in level of difficulty. Another thing to bear in mind is that it will take several years before you see flowers on your new plants. In [late] summer, you would sow fresh seeds in pots and “provide two periods of chilling, such as two cold winters, with warmth between. Seeds are doubly dormant (roots emerge in the first year and seed leaves in the second). Guard against mice: they love the seeds.”
Another description of propagating from seed may be found in Jekka McVicar’s book Seeds (Lyons Press, 2003):
This seed has a double dormancy, producing roots in its first year and
leaves in its second. It needs two cold periods, with warmth in between.Collect ripe, fresh seeds in early autumn. Sow individually in pots,
using standard soil-less seed mix, either peat or peat substitute mixed
with coarse horticultural sand. Mix to a ratio of 1 part soil-less mix +
1 part sand. Cover with coarse grit, then place outside exposed to all
weathers. Visible germination occurs during the second spring. Grow on in
a cold frame for 2 years before planting out.
Excerpt on propagation methods from Plants for a Future database:
Seed – best sown as soon as it is ripe in a cold frame.When sown fresh,
the seed produces a root about 6 weeks after sowing with shoots formed in
the spring. Stored seed is much slower, it should be sown as soon as
possible in a cold frame but may take 18 months or more to germinate. The
roots are very sensitive to disturbance, so many growers allow the
seedlings to remain in their pots for 2 growing seasons before potting
them up. This allows a better root system to develop that is more
resilient to disturbance.If following this practice, make sure you sow
the seed thinly, and give regular liquid feeds in the growing season to
ensure the plants are well fed. We usually prick out the seedlings into
individual pots as soon as they are large enough to handle, and then grow
them on in a cold frame for at least two growing seasons before planting
them out when they are in growth in the spring.
The Heartland Peony Society has an illustrated tutorial on grafting tree peonies, should you wish to try this method.
Our neighborhood has a small planter area at its entrance. There is no water supply to this area, but a nearby resident is willing to water occasionally. The soil contains much clay. We would like to plant a few drought-tolerant annuals to add color and supplement the more permanent shrubs–such as boxwood–planted in the area. Can you recommend some plant choices? How could we amend the soil to best hold water during the upcoming dry months? Would a commercial product such as “Quench” be of any value, in addition to organic mulches?
I found the following article by Nikki Phipps on GardeningKnowHow.com about drought-tolerant container planting. Here is an excerpt:
“…many plants not only thrive in containers but will tolerate hot, dry conditions as well. Some of these include annuals like marigolds, zinnias, salvia, verbenas, and a variety of daisies. Numerous perennials can be used in a xeriscape container garden such as Artemisia, sedum, lavender, coreopsis, Shasta daisy, liatris, yarrow, coneflower and more. There is even room for herbs and vegetables in the xeriscape container garden. Try growing oregano, sage, rosemary, and thyme. Vegetables actually do quite well in containers, especially the dwarf or bush varieties. There are also numerous ornamental grasses and succulents that perform nicely in containers as well.”
This Brooklyn Botanic Garden’s 2001 article provides a list of drought-tolerant plants for containers.
I had not heard of Quench, but since it is cornstarch-based, it is certainly preferable to the hydrogel and polymer products which are more widely available. I found an article by garden writer Ann Lovejoy in the Seattle P-I (June 3, 2006) about Quench. Here is an excerpt:
With pots and containers, mix dry Quench into the top 12 inches of potting soil in each pot and top off with plain compost. Few roots will penetrate deeper than a foot, so it isn’t very useful down in the depths of really big pots unless you are combining shrubs and perennials.
I would not recommend hydrogels or polymers as a soil amendment. Professor Linda Chalker-Scott of Washington State University has written about these products and their potential hazards. Here is a link to a PDF.
You could consider applying a liquid fertilizer (diluted seaweed-fish emulsion would work) to your containers once every week or two during summer. Here is an excerpt on some general information on container maintenance, from a no longer available Ohio State University Extension article. Excerpt:
“Once planted, watering will be your most frequent maintenance chore, especially if you are growing plants in clay containers. On hot, sunny days small containers may need watering twice. Water completely so that water drains through the drainage hole and runs off. Water early in the day.
“If you incorporated a slow release fertilizer into the potting mix, you may not need to fertilize the rest of the season; some of these fertilizers last up to nine months. You can also use a water-soluble fertilizer and apply it according to the label directions during the season.
“Mulch can be applied over the container mix to conserve moisture and moderate summer temperatures. Apply about one inch deep.
“Depending on the plants you are growing, you will need to deadhead and prune as needed through the season. Monitor frequently for pests such as spider mites. Pests usually build up rapidly in containers.”
I was recently given 6 Oriental lily (Lilium) bulbs – bare root. It seems much too cold (late February) to put these in the ground. They are currently naked in the garage, but would it be better to pot them until the ground is workable? I have not raised lilies before, other than daylilies.
Generally, it is good to plant bulbs soon after you get them, but if you need to wait (due to cold weather and unworkable soil), keep the bulbs somewhere cool, and keep them “in moist sand or peat moss until scales plump up and new roots begin to sprout” (Sunset Western Garden Book, edited by Kathleen Norris Brenzel, 2001).
The Gardener’s Guide to Growing Lilies by Michael Jefferson-Brown and Harris Howland (Timber Press, 1995) confirms your thought that it is too cold to plant them out in the garden (I would wait until the threat of freezing temperatures subsides). According to the resource mentioned above, your lilies will do very well in pots, so what you could do is pot them now, and if you decide you would like to move them into the garden when it warms up, you could either put them, pot and all, into the border, or gently remove them from the pot without too much root disturbance, and plant them in the soil.
My question is about Cytisus. People with allergies complain about the Scotch broom that grows wild. Are the other tame varieties like C. x praecox going to be a pollen allergy problem also? I want to plant it as an informal hedge and my customers are worried. I want to tell them there is no comparison in the plants. Am I right?
To answer your second question first, Scotch broom (Cytisus scoparius) is an invasive European species that has given all brooms a bad name. Spanish broom (Spartium junceum) is also invasive, and is considered a Class A noxious weed in Washington State. There are garden-worthy brooms such as C. x praecox. A staff member here grew one in her previous garden for many years (and loved it). Some species of Genista, such as Genista stenopetala, are reportedly not invasive.
According to the book Allergy-Free Gardening by Thomas Leo Ogren (Ten Speed Press, 2000), Cytisus ranks 5 on the allergy index scale of 1 to 10, but allergy to this plant is uncommon, except in areas where there is a lot of it growing. Spartium junceum rates a 7, while Genista rates a 4, about the same as a begonia or a primrose.
I would like to transplant a Japanese maple, probably 5 years old and about 8 feet tall. Can I do it in late October/November safely in St. Louis? And what is the best method?
Japanese maples are best transplanted when they are dormant—usually late fall through early spring if the ground does not freeze in your area.
The following information comes from Japanese Maples (by J.D. Vertrees, 2001, pp.61-62). This book also contains good information about mulching and general care:
When moving a plant to a different location within a garden, the plant must be dug with an earthen ball intact around the roots. If the plant is of any size or age, this root protection is important. It is also desirable that the planting hole be prepared in advance, ready to receive the plant with its root ball, as soon as it is dug up. Having the new planting hole ready minimizes the risk of the fine feeding roots drying out. For this reason it is imperative that, whatever method, material, or timing is used when planting a Japanese maple, the roots are not exposed to air or direct sunlight for any length of time. Such care will help prevent them from becoming desiccated, which would cause too much transplant shock and possible loss of the tree.
The planting hole should be dug slightly larger than the root mass of the plant. To enable the root system to establish itself quickly, it helps to mix with the soil organic compost, such as composted conifer bark mulch, rhododendron or azalea planting mix, or rose compost. In tight , heavy clay soils the compost helps condition the soil, while in light, sandy soils the compost assists in water retention. Sawdust or wood chippings should never be used as, during their breakdown, they use up the available soil nitrogen and render it unavailable to the newly planted tree.
The planting hole should be deep enough so that the root collar of the plant, the ground line at which the young plant was grown, is level with the ground surface. The exception to this rule applies to tight, heavy soils, like clay, where success will be greater if the hole is rather shallow so that the root system is partly above the ground level. When filling in the hole, the soil should then be mounded up to the root collar to protect the roots from drying out. If deep holes are dug in heavy soil, it is like planting the tree in a large iron kettle with no drainage. Surely the plant will soon drown and die.
Whatever the soil conditions, the tree should never be planted deeper than the root collar. After the first season or two, the plant will find the level of root activity at which it can exist in particular soil conditions. I have observed maples growing in some surprisingly dry, shallow, and exposed conditions.
Can you suggest some shade shrubs/low trees that could be used in the bottom quarter of a huge, years-old pile of yardwaste and branches that is now a 20 foot cliff? I have started with some Vinca minor in the lower part but could use some ideas of some things to plant that might get 15 feet tall, evergreen, and grow in woods/shade or sun through trees.
The closest list I could find to meet your needs is one of evergreen shrubs that will grow in shade:
Japanese aucuba – Aucuba japonica vars.
common boxwood – Buxus sempervirens
camellia – Camellia sp.
gilt edge silverberry – Elaeagnus x ebbingei ‘Gilt Edge’
Euonymus – Euonymus fortunei radicans
Japanese aralia – Fatsia japonica
drooping Leucothoe – Leucothoe fontanesiana
Oregon grape – Mahonia aquifolium
Burmese mahonia – Mahonia lomariifolia
longleaf mahonia – Mahonia nervosa
holly leaf osmanthus – Osmanthus heterophyllus vars.
English laurel – Prunus laurocerasus ‘Mount Vernon’
Japanese skimmia – Skimmia japonica
evergreen huckleberry – Vaccinium ovatum
nannyberry – Viburnum lentago
Source: The Pacific Northwest Gardener’s Book of Lists, by R. & J. McNeilan, 1997, p. 46-47