North Shore Gardener July 2007

Rose Garden

Photo: RWBarger

July 11, 2007: Dry, dark landscaping, Coleus, Peonies

Peonies
Q: What is the best way to cut back my peonies now that the flowers are starting to die? Thanks, KGP

A: Cut just the dead flower heads after they've bloomed, but allow the foliage to grow all summer. In the fall, when frost has killed the greenery, cut back to about four inches high for the winter. Remember to remove and destroy all dead leaves and stems to prevent disease. A lot of gardeners are now recommending that you also change mulch around peonies every year to prevent disease. Don't you wish we could have peonies blooming all summer? Maybe someday some plant geneticist will develop one that does just that!

Coleus
Q: I have a lovely coleus that a friend gave me last fall. The edges of its leaves are lime green and the middle is a burgundy or cerise color. Very pretty!!! It has really grown over the winter, and I would like to plant it outside. When would be a good time to do this, and should it be planted in partial shade or total shade?? L.R.

A: Yes, the coleus can certainly go outside, when the weather is warm! The rule for taking houseplants out for the summer is to wait until the night temperatures are reliably in the 50 degree range - if you jump the gun and put potted plants out on sunny, warm days, you're going to spend a lot worrisome evenings, hauling plants inside during a cold night - or risk damaging them. Coleus does well in a container or planted .in the garden, in dappled sunlight, or even shade, but not hot sun. After living indoors all winter, it is necessary to make the transition to outdoor brightness gradually. Water coleus well during hot spells, fertilize lightly all season- and do snip off any flower stalks that appear - you want the colorful foliage, not necessarily the tiny flowers. If the plant has grown too large or is slightly gangly, please consider cutting a few of the longer stems and rooting them in water or soil - this is one of the easiest plants to root - and from the description of the colors, I'm sure your friends would love a cutting! These smaller plants will be nice to bring in next fall...And the "mother plant" benefits from this pruning and will grow thick and bushy.

Dry, dark landscaping
Q: I live in a condo in Salem. The whole area that would be our lawn is built on top of blasted ledge and broken stone of various sizes with a thin layer of earth on top. The pine trees that were planted around the edge for privacy by the builder in 1987 really don’t have any manner of a deep root system and have grown to about 30 feet in height with the lower branches all dead. The roots from the nine trees have grown under and over the area that would be for grass. And the trees shade the sunlight. The pine needles are supposed to be so acid that they also kill the grass. The condo ass has given up trying to grow anything and has left us to grow something on this land. I have added a large amount of soil a few times and I have placed sod all at my expense and tried all of the garden shop remedies over the last twenty years. I there any type of vegetation, vine, ground cover or whatever that I can plant on this space that would cover the bare earth without spending large amounts of money. I do read your column in the Salem News and I have a copy from about a year ago about the Gout Weed and planting moss. There is plenty of moss in the woods across the street from the house that might be transplanted. Would moss grow in this area?

I would really appreciate any recommendations that you might offer. W.L.B.

A: You certainly have a problem area in which to grow plants! You idea of growing mosses and making a moss garden would be quite different and beautiful – and would probably do well in the deep shade/high acid area. But moss requires a lot of moisture as well, season after season, year after year. You didn’t mention that you want to add irrigation to your cost, but I assumed you wouldn’t! And besides the water, a moss garden does require some intricate hand weeding to keep it looking as beautiful and velvety as possible. SO – first I would suggest a soil test to reveal the exact amount of acidity – you may be pleasantly surprised, since you may have altered the soil with your addition of topsoil and anything else you might have used, trying for a “fix”! I will suggest a few plants – they will tolerate a deep shade/dry planting, but you have to remember the word “tolerate” – they will certainly grow and, in some cases, bloom - but not as well as they would in better soil and a little water. –and most of the flowers are small…. Most of these plants have shallow root requirements, with the hosta needing the most depth– and plants could be dug in-between some of the tree roots. Please note that the first growing season, you would need to apply additional water, even to dry loving plants. No matter what you plant, deep mulch would add to the moisture retention in the problem area, and keep it relatively weed-free and clean:

Goutweed is certainly a choice – with the variegated foliage and tiny flower, it will spread in time, and reseeds itself readily……

Heuchera or “Coral bells” has interesting and attractive foliage, and thin stems of tiny flowers…..

Hostas require less water than you think, and can be had in both solid green foliage and variegated, which are stunning in a dark planting area. Flower stalks in mid-summer are a plus.

Japanese painted fern, a fern with silvery streaks on the foliage, also brightens dark areas.

And don’t forget Lily of the Valley – spreads, remains green from frost to frost, and has sweet-smelling flowers in spring!

The lower branches of the pine trees should be removed – they are unsightly, dead and certainly won’t regenerate.

This week’s dirt…………………………………………………………
To B.G of Danvers: No, you cannot use a weed killer on a flower bed to get rid of the wild violets without risking the perennials that you want to keep. You have to remove them by hand – or sacrifice the perennials! Sorry to be so late in answering – next time, please be sure to put your address in the body of the letter as well as on the envelope!

Water accurately! Aim your sprinkler or any watering device carefully – don’t let it run it against the house or fence. Water causes expansion/contraction of the wood and promotes rot and mildew, and peeling, and cracks in the paint. Watering accurately also saves water.

July 18, 2007: Poppies, Iris not blooming, Hardy Hibiscus, Reader’s idea for easier watering of a strawberry jar, Reader’s warning about mulching too close to trunk of tree

Irises
Q: My question is about irises. I have tried twice to grow them, but all I get are beautiful leaves, but no blossoms. What am I doing wrong? Someone said I may have planted them too deep. Thanks for your help.

A: I assume these are bearded iris. Your iris may indeed be planted improperly. ...and that may be the reason they're not blooming. They should be planted just barely under the surface of the soil in a totally sunny area. If you use winter mulch, be sure to remove it very early in the spring so you don't smother the roots. Be sure drainage is excellent – roots rot in wet soil. But give them additional water the first year after planting if the weather is dry. Be sure to keep the bed well-weeded - iris won't stand for weed competition! Divide plants every few years for best bloom, replanting at the same shallow depth. And beware of fertilizers with a high nitrogen formula - high nitrogen produces lush foliage, but not flowers. Could a high nitrogen fertilizer from your lawn have found its way into the iris bed?

Hardy Hibiscus
Q: I read your column in the Eagle Tribune weekly. I would like to have a few questions answered on Hardy Hibiscus. I have grown a few varieties of this beautiful, large flowered plant for 3 years now, and would like to know if they transplant easily and, if so, when is the best time to do this? I would also like to know if they should be divided and, if so, when and how. Also, what about maintenance (pruning)? I have heard that the growing plant, which breaks ground late in the spring, should be cut back to half its size when it reaches about 18 inches. In the past, I have not cut my plants back. Any and all information you might have on the Hardy Hibiscus would be of value to me and greatly appreciated.

Thank you, R.

A: The hardy hibiscus is a spectacular perennial bush. It dies back to the ground every winter - a rough pruning should be done in late fall, with a heavy pruning done in early spring - prune to a few inches from the ground in early spring. This will promote the saucer-sized flowers, as it flowers on the new wood. As you know, hardy hibiscus is slow to grow in the spring - it may be the very latest shrub to sprout each year. I suspect that many of the plants are removed or replaced by anxious gardeners who think they are dead! Divide or transplant in the early spring before they break dormancy. Very few gardeners choose to divide, they go for SIZE instead! It’s fairly easy to do: Take as large a root ball as you can manage. Dig the planting hole and amend with compost. Do dividing with a sharp spade, cutting and replanting as quickly as possible - and be prepared to water hibiscus for the season ahead.....Water is important to the plant whether it is a new plant or old...Transplanting or dividing can be done in the fall or in early spring, before the plants break dormancy, but fall is best.

Poppies
Q: I wrote you last year and received great advice about my peonies. This year I have two more flower questions. A lady near me has gorgeous orange flowers, about the size of a quarter. She doesn't know the name, but says they are in the poppy family. They do look like miniature poppies. Do you know the name and where I might find some to plant?

A: I think that what your neighbor has is some California poppies. Do you remember the line in the John McCrae poem, "In Flanders fields the poppies blow, between the crosses, row on row."?....or the beautiful field of red poppies in the "Wizard of Oz" where Dorothy and her friends are lured to sleep by the wicked witch? All poppies have long been associated with sleep and death - and these were both types of beautiful annual California poppies and symbols of deep sleep -

California poppies are the state flower of California. This wildflower is considered a self-sowing annual, and is easily grown from seed, directly sown in the late spring. They are available in many bright colors - and are almost as beautiful as our perennial Oriental poppies. Seed for California poppies is available at garden centers in early in the spring and year-round at www.Americanmeadows.com.

-So glad to hear that the peonies are thriving!

From a reader: Watering beehive jar
I've always had trouble effectively watering the beehive pots I use for the pansies ... water poured into the top tends to just flow out the side scoops. So this year I tried something new: I took a length of 3/4" PVC pipe, cut it off so it was just an inch more than the depth of the soil in the pot, cross drilled it with 1/4" holes every inch or so, and drove it down into the center of the beehive pot. Had to pull it back out and clear the soil, but now I water into it and the water is evenly distributed throughout the pot from the center. The flowers have never looked better. D. B.

A: - Love your idea for watering the beehive jars (I'm so glad you sent pictures – I must admit that I've always called them "strawberry jars", and I couldn't imagine what you were planting in "beehives" - !) Next year, could you have someone hold the pipe in place - and then fill the pot with soil as you plant? It would keep most of the soil out of the pipe, although I wouldn't think a little soil would matter much.....Even with soil-clogged holes, the pipes would still seep water into the pipe......the pansies sure look happy and so pretty at your front door!

From an eagle-eyed reader: trees improperly mulched by professionals!
Mrs. S.P of Danvers writes us to point out the glaring error in planting the trees around Liberty Tree Mall. The landscaper has mounded up the mulch like a teepee around the base of each tree. We understand that this might make the job of maintenance a tiny bit simpler – but at what expense? Several trees have already died. A reminder to all gardeners: Keep mulch at least 6 inches away from the base of any plant – it can harbor all sorts of pests! Thank you, Mrs.S.P.

This week’s dirt…………………………………………………………
Water hanging baskets daily- – hanging basket dry out as fast as laundry on the line, particularly if humidity is low. And plants under an overhang don’t get the benefit of rain!

July 25, 2007: Wood mulch, Lilacs drowning , Mandevilla repotting

Mandevilla repotting
Q: I am in the process of re-potting my mandevilla and I am not sure what to do. I took it out of the large pot that is has been in for two years, and wanted to put new soil in. When I washed all the soil off the roots, there are so many tubers attached to the plant that I don't know whether to pull any of them off or just repot the plant as it is. I would appreciate any info from you. I hope I explained my predicament well enough. R.-

A: No need to remove the tubers – although there is some controversy as to whether good, new plants can be grown from the tubers - it might be worth a try! Be sure there are several eyes on each tuber. But otherwise, there is no need to remove them - tubers store food and the plant is obviously healthy, and is using them. You are doing a very complete and thorough job of repotting by taking the time to rinse the roots - I admit I would have just removed it from the pot, shaken off any excess dirt, loosened the roots if necessary - and replanted in fresh bagged soil and maybe given it a larger pot! Your method, though, should show superior results later in the summer when the plant blooms!

Lilacs drowning
Q: I have several lilac bushes that sat 6 inches deep in water during the 2006 Mother's Day Flooding. It took approximately five days before the water in my neighbor's yard receded. The leaves on half of the bushes turned brown and fell off. This spring two bushes produced about 10% of their normal foliage, mostly at the top of the bushes. I pruned here and there where the branches looked completely dead. What are the odds that these plants will make a full recovery? I have invested much time and energy, and will wait another growing season if you think they will come back? Should I give them another year and see what happens, or take them out all together. They are 7 feet tall and an eyesore. -Amesbury, MA

A: I'm a plant saver! With seven-foot lilacs, I think it would be well worth another season's wait. I know it will be painful to you to watch dead branches for another year, but be very careful what you prune, until you're sure it's dead. Flooding will certainly destroy roots - a week doesn't seem to be enough to kill them all - but remember that the ground remained saturated for days and days after the water appeared to drain off. My vote would be to wait till next spring to make your decision! Seven-foot lilacs are irreplaceable!

Wood mulches
Q: As a beginning gardener I went to a nursery to buy some mulch for my young lilac trees only to be confused by the many types of mulch available, pine, dark mulch, spruce, hemlock, cedar, and some red dyed types. I knew I didn't want mulch that has red dye in it as I assumed it would not be good for the environment. Could you enlighten me on the differences on the mulches? Are price and color the only considerations? Thanks, Rhoda

A: Wood mulch is used to hold the moisture in the soil and control the soil temperature (your lilacs will appreciate it!) - mulched beds are slower to warm up in the spring and slower to cool down in fall. As you mention, there are differences between the kinds of mulch you see at the nursery - price being just one of them! Most of the wood mulches are colored, many using a vegetable dye - and by colored, I don't mean just red or blue or green (yes, you COULD get a mulch to match your house - or your eyes, whatever!!) Mulches are also colored with red or brown or black to make the mulch acceptable to most gardeners who want a natural, uniform color mulch that looks like rich composted material - and colored mulch does hold its fresh look longer than naturally colored wood mulch. The dyes used are generally safe - but read the bag or ask to be sure! Most dyes on mulches won't rub off on your clothes if you or the kids sit or kneel in it! If you choose to use colored mulch, be sure to buy enough to cover the given area, so it will match. How much should you buy? Figure the area: multiply the length times the width, times about four inches deep - and take these figures along when you buy. Any colored mulch may fade after a year or two, and can be restored by replacing completely by digging in or removing it and adding a fresh layer on to the top. A light raking will often restore the "new" appearance to a mulched bed, too. Be sure to water the area well before or immediately after applying mulch - otherwise, the mulch could form a barrier to needed water...or soak water away from the plants, just as a layer of dry peat moss will. Termites are attracted to wood fiber - so if you have trouble with termites, keep wood mulch back at least a foot from wooden buildings - some gardeners put down a termite barrier in the space between the mulch and the building. Generally, termites prefer a larger chunk of wood, not shredded mulch.

A few kinds of wood mulch and what to look for:

Ask to see a sample - mulches are available in many size pieces of chips and chunks and shredded varieties. A finer mulch will decompose faster - and might blow or wash down a hilly area faster than a larger chunk. But a larger chunk might float away in a very wet are!

Labeling:

Bags labeled "bark mulch" must be 85% of the listed kind of bark- cedar, pine, cypress, etc.

Bags labeled "mulch" only have to be 70% of the named variety - and could be ANYTHING else, although usually a wood....

Pine bark - for general landscaping and garden use... Pine bark tends to hold its color better than other mulches – and smells good, too!

Probably the cheapest and most commonly available mulch in the Northeast, depending on where and how you buy it. Mulch is sold by the bag - or more economically, by the cubic yard by the truck-load – have it delivered and buy it this way - share with a neighbor for real economy.

Red cedar - smells wonderful, like a cedar closet! A light brown color.

Cedar chips – coarser than cedar mulch, good for paths and play and picnic areas. Chips are cheaper than cedar mulch.

Cypress - from the Deep South, last longer than other wood mulches. Light in color...

Of course, there are many other kinds of mulch - this just touches on the wood mulch group! If you need more information, please write!

This week’s dirt…………………………………………………………
We’re more than halfway through the grass growing season now - have you sharpened your mower blades lately? By now, they need it! Dull blades tear the grass – and grass which is torn, rather than sharply cut, will look inexplicably yellow/brown a few days after mowing instead of healthy green. Sharpen the blades! And continue cutting high during hot weather for the health of your grass – remove not more than 1/3 of the blade in a single cutting.