Horticulture Guy

Q. This year I had lots of moss in my flower garden. Although I have had
patches of moss on other places before, I don’t remember much in my
garden areas. It’s gone now, having had my bed cleaned up for the
winter, but how do I keep it from coming back or killing it if it
does, without hurting my flowers? Sure miss your column in the Tacoma News Tribune.
The new format is not nearly as relevant. Betty Garrison - Tacoma, WA
A. The best way to get rid of moss is to do the opposite of if you wanted it to grow. It prefers a firm acidic substrate (it doesn’t have roots but does have root like structures that help keep it in place) plenty of moisture as well as indirect sunlight (thus why it loves the north side of roofs better than southern side). So if you have poor drainage improve it by adding organic matter to the soil and working it in. cultivate the surface of the soil each month (this also helps control weeds) with a hoe or similar cultivating tool. Check the pH of the soil. Unless you are growing acid loving plants like rhodies and azaleas add lime to bring the pH up just below neutral (6.8 -6.9). And if possible prune the exising plants to allow more light to the soil surface. You can also help the process by using a natural moss control product like Moss and Algae Killer. - HG

Q. I have an apple tree about 15-20 yrs old. It bore lots of healthy fruit, but I couldn’t reach 3/4 of it. I don’t think it has ever been pruned. I know which limbs to take out, but how aggressive can I be, and when should I prune? Also, can I cut back the length of the branches, or the height of the tree? I miss your column, but am glad to find you online. Thanks! Marty Fisher, Orting, WA

A. Actually you can be fairly drastic especially with any vertical growth but as you guessed timing is important.  Since you seem to be familiar with what the shape should be (I know which limbs to take out) I’ll just reiterate for others that may read this.  The best shape for the apple is to have an open center.  So your goal is to open up the center and thin things out so that light can get into the center of the tree. Pruning now would likely result in loss of fruit this coming season and possible overgrowth of new shoots since the tree will have the energy it would have used on fruit production on new excessive growth. Vertical branches bear less fruit than more horizontal ones so a few of those could be removed now in the dormant season. I would wait until you see the fruit set in the late spring and then go in and get that tree back into shape being sure to leave a crop of apples to enjoy.

Q. Yes I miss your column. I’m looking for recommendations of native trees to plant on our parking strip, which is on the North side of the house.  These are to replace the two matching winter flowering Japanese flowering ones I need to have removed because one has died. I think natives will have a better chance. Lily Warnick - Gig Harbor, WA

A.  Well since you say that the strip is on the north side of the house I will assume that it is either a shady or partially shaded area, which limits the number of native trees that would be appropriate.  If you would like to stay in the cherry genus there is a native Bitter Cherry (Prunus emarginata var. mollis), which may be suitable.  Be sure not to get the “var. emarginata” which is more spreading and shrub like.  Although the flowers are not quite as showy the Cascara or buckthorn (Rhamnus purshiana) is another option if the soil is on the moist side.  A Pacific Dogwood (Cornus nutallii) is another showier alternative although it is somewhat susceptible to the fungal disease anthracnose.  Breeders are actively working on disease resistant varieties of this. 

Q. Peter, I dug up irises from a bed over-run with grass, with a grand plan for making a raised bed lined with landscape cloth to keep the grass out, but what in the world should I do to keep the irises alive until hubby makes that bed for me? Keep them- not him- out in the air? Stick them in perlite? Plant them somewhere else for a while? Have I killed them? They have been out of the ground for 5 days. Sure would appreciate your words of wisdom. Many thanks! Linda S. - Lakewood, WA

A.   Yes you should plant them somewhere else for a while.  This is called “heeling them in”.  You simply dig a trench in another section of the garden and line them up in the trench at about their same growing level in the grass infested bed and cover with soil until you are ready to put them back in the reclaimed bed. Water them in the unlikely event there is no rainfall.

Q. We have an old, large maple tree in our yard.  It does not have as many leaves as it used to.  It appears to be slowly dying.  Many years ago we put a raised rock bed around the tree and planted a few items.  The dirt is about one foot high.  Could that have been distressing the tree over the years?  We plan to knock the rockery bed out and take the excess dirt away.  We’ve also had woodpeckers creating sap drips and wondered if they were causing the problem.  Do you think we can save the tree by taking the dirt away?  Or is it too late?  Thanks, Jan - Tacoma, WA

A.  Yes I believe the raised bed around the tree is exactly why you are seeing a decline in the Maple.  Changes in soil level above trees roots reduce oxygen levels for the root system effectively suffocating the tree.  If the root surface area is large enough will completely kill a tree very quickly.  If the tree still shows signs of life removing the excess dirt may allow the Maple to recover.  The woodpeckers are likely a symptom and not the cause of the Maple tree’s decline.  

Q. I would like to start some emerald green arborvitae from cuttings this fall. What steps should I take to ensure successful propagation? Thank you. Mark Bruser - Tacoma, WA

A. Cuttings for Arborvitaes (Thuja) can be taken from summer to mid fall and should not be fully ripe but rather semi-ripe. Although you can try now with ripe wood but you should use rooting powder to aid in root formation. The cutting taken should be from current season’s growth but should also include a sliver (or heel) from the older wood to aid in rooting. This is called a heel cutting and is usually achieved by pulling the cutting from the main stem sideways thus removing some of the bark. Place the cuttings in a well-aerated mix of half Perlite (or pumice) and half peat moss (or coco peat ) which has been moistened. Place the cuttings in a plastic bag or humidome monitoring the moisture levels. A heat mat is also beneficial as it speeds up the rooting process.

Q. I have a 10-year-old camellia tree that is growing out of control. It is located in the West corner of the house and gets a lot of western sun.  I trimmed just the top last year and this year cut back to the trunk some of the lower branches.  It is located next to my dining room window and don’t want it to block the view completely.  It blooms greatly.  How much can I trim it back and when?  Do I have to trim it every year since it seems to like my trimming? Thank you, Patricia Stolp - Spanaway, WA

A. Well I don’t know how big your dining room window is but your camellia will be wanting to be a minimum of 8 feet tall and a little more than half as wide.  That is a minimum.  So you may need to cut it back yearly to keep a view out of your window.  Fortunately they are generally respond well to heavy pruning - rarely dying back from it.  If you don’t want to loose blooms then prune them just after they finish blooming.  Make what are called heading cuts (removing part of the limb) back into the interior of the shrub.  Or when necessary you can perform thinning cuts as you did on the lower branches where the entire branch is removed. 

Q. We just moved into a new house. There are several existing fruit trees, most of them are damaged looking. I don’t think they had much water or care prior to us. Will simply watering and fertilizing bring them back or?  Mick Davis (Member)- Tacoma Washington (Spanway area)

A. Regular watering and fertilization will definately help but I would also recommend some judicious pruning. You can download a free Adobe Acrobat (.pdf) file from the Extension website called Training and Pruning Your Home Orchard. This would be a great resource to get you started.

Q. Is there a local source to buy trees? We would like to use Pines and Firs to complement the natural trees. Mick Davis (Member) - Tacoma Washington

A. If you are looking for small quantities of native firs and pines then looking up local nurseries in your yellow pages is an option. You can also find specialty nurseries like Woodbrook Nursery in Gig Harbor. Or you can go to a Washinton Native Plant Society Plant Sale. There is one coming up in this month up in Seattle (October 14th, 2006). If you are interested in larger quantities (at least 100 of a species) then you may consider Webster Forest Nursery in Olympia.

Q. We have a fir tree that has vines growing up it. Is this damaging to the tree? Mick Davis (Member) - Tacoma Washington (Spanway area)

A. It is very likely that you have English Ivy (Hedera helix) growing up your Fir trees.  It is very invasive in the Pacific Northwest.  The potential damage is two fold.  First the evergreen vines of the English Ivy will increase the wind resistance of the tree making it more vulnerable to blow overs as can often happen during our winter windstorms.  Second if the tree is small enough the ivy can get up to the crown and smother the tree.  This is not as common in Douglas Fir (due to their growth rate) but it can happen in many other trees. The Ivy does not attack the tree directly and the attaching structures do not penetrate the bark of the tree.  I always recommend the removal of Ivy from trees.