Horticulture Guy

Q. I live in Lakewood in a large, beautiful gated condominium community of 65 single story duplexes. It was built in a vacated gravel pit. On three sides of the development, we have steep banks sloping down to our units varying from 40 to 45 degrees.  On one street in particular, which is the 45 degree slope, has a bulkhead varying from 4 ft. high, down to 2 ft. high. In back of the bulkhead, the 45-degree slope varies in the length of the slope from 10ft. to 15 ft. to our perimeter fence. This bank slopes up to the south. Our neighbors along the perimeter fence above have tall evergreen and leafed trees shading this area most of the day. The only thing that has been done to this area in the past is put down a rope type netting and bark on the rock, sand & gravel, then try to get ivy to grow, by only putting soil in each hole that a ivy plant was planted. The decayed bark slides down and over the bulkhead in places. The bordering evergreen trees shed their needles on this area increasing the acidity of the soil. I say that we have to remove the fluffy decayed bark, apply a good grade of topsoil and plant something that will develop a good root system to hold the bank, that does not need much sun, would enhance the beauty and be easy to maintain. O yes, I forgot, we have deer that do get hungry and are a nescience to our residents growing roses etc. I know that our problem is a challenge, but I know from my past questions, that from my former requests that you can handle this one.     Thank you, Don Berglund - Lakewood, WA

A.  Holy Rubik’s Cube Batman - You’d make the Riddler blush! One anomaly I notice is that you say that the slope is to the south and there are trees above which shade the slope.  Do they overhang the slope?  If my high school geometry is still intact the trees above should be to the north of the slope which should allow light into the area.  I agree that Ivy grown in little pockets of soil will not provide the  stabilization you may be looking for.  I would lean toward soil stabilizing shrubs.  Here are two ideas and caveats in order of my preference:

Salal (Gaultheria shallon) native evergreen tolerates shade, sun, moist or dry soil.  It is also deer resistant. 3-7 feet tall. (Native)

Red Osier Dogwood (Cornus sericea or C. stolonifera) great soil stabilizer and has beautiful red stems.  Tolerates shade and won’t need as much water if partially shaded. It is susceptible to deer browse but this may not be too great of an issue since you will want to cut them back each season since they are grown more for their colorful red stems (which disappear with age) than their flowers.  Each year it is cut back during the dormant season to maintain the red stems.   (Native)

-- HG

Q. In last week’s TNT you discussed Helleborus argutifolius. You mentioned that it will probably die after 5 or 6 years. I this the case with all Helleborus? I have recently purchased a Helleborus Orientalis Mrs Betty Ranicar.

A. I believe this is specific to the species since the most hellebores can live upwards of 15 years. Helleborus argutifolius is the only species I have seen noted as a short lived perennial (which connotes 4-5 year lifespan).  It should be noted that as a group herbaceous perennials can vary widely on their lifespan.  For example I know people who have passes on peonies from generation to generation.  Of course the minimum to be considered a perennial is two years but beyond that has to do with the environment and the genetics of the plant.  This means both as a group - as I say in this case the species Helleborus argutifolius is short lived - and as individuals.  Individuals within a species can buck the trend.  This is something that often comes up with the Blue Poppy as well.  Many strains are short lived, while others can remain for years.  It is sometimes difficult to determine if this is due to their genetic makeup or due to the conditions they are grown in.  The Blue Poppy is susceptible to crown rot.  In their native lands in the Himalayas they are coved in snow all winter.  Here they are not and if they are not well drained a film of water on the soil surface can freeze compressing and damaging the crown.  This is often why Blue Poppies may only last a few seasons.  This is why I have seen recommendations to remove the top inch of soil around the crown of the plants and fill with sharp sand, pumice or Perlite to prevent a film of water from forming.  If you have a known short lived plant then it is good to plan ahead for replacements.  Sometimes as in the case with the hellebores they can self seed and provide free replacements.

-- HG

Q. I have a wisteria that is climbing up and around and around a large fir tree.  Will it damage my fir tree? Pat Stougard - Vashon Island, WA

A. Wisteria are considered a problem when growing over or on woody trees and shrubs.  They can strangle smaller specimens and if they reach to top of the tree or shrub will also kill by shading.  They are not killing parasitically the way mistletoe does - by tapping right into the tree and extracting nutrients.  Instead they wrap around and try to outgrow the tree or shrub to get to the best light. Now your large fir tree may be so big it would never reach to top to completely shade it out but it will kill off lower branches of the tree as it climbs.  In addition it adds more drag force to the tree when we have windstorms. This increases the chances that your tree will succumb to a blow down.  It is usually best to train wisteria to a man made structure and keep it managed.

-- HG

Q. In the paper this morning, you mentioned thin the apple trees in the light or heavy year.  How can one tell which year it is?  We have 2 apple trees grown on wires.  They need trimming but should I do it now?  Thank You Marcy Volny - Puyallup, WA

A. If you are not sure then you probably haven’t had the trees bearing for a many years or your trees do not exhibit this pattern. For example, a tree will have a bumper crop (get out the canning equipment!) in one year alternating with bearing just enough apples to eat fresh in the next.  If you are not sure then simply thin out one fruit per cluster and make sure each cluster is at least a fist width away from another cluster.  If it is not remove one of the clusters fruit entirely.  It sounds like you have an espaliered apple and because of the restrictions placed on the tree by putting it into a single plane they may not exhibit this biennial bearing phenomenon. 

-- HG

Q. Hi Peter, I have what I believe is a Hellebores argutifolius that has done surprisingly well for the last few years in a hot, dry area next to a cedar tree. It has clusters of yellow-green flowers and sawtoothed leaves and is about 3′ high and around. It’s starting to look a little leggy this year and I was wondering if it should be cut back or otherwise cared for. Normally I just cut the flower clusters off when they begin to fade. The foliage stays nice year round. Thanks, Henry Raynor - Puyallup, WA

A. This description does sound like Helleborus argutifolius (Syn. H. corsicus) or Corsican Hellebore.   It is understandable that you are having good luck with this species in a hot, sunny and dry area. Although most Hellebores are prefer partial sites that are shade to shade these are native to the sunny climes of Sardinia and Corsica - Mediterranean islands).   In their native lands the foliage is evergreen as it tends to be around the Puget Sound but in cooler parts of our country they can die back to the ground.  Usually just cleaning up old flower stalks and tattered leaf stalks is sufficient grooming for these plants.  But you can also give them a haircut (to the ground) in the late winter before they send up the flower stalks (this is optional and not usually necessary with evergreen hellebores).  In addition after a few years they may need some fertilization as well - test the soil in the root zone.   I am not sure how many years you have had them but their life expectancy is usually in the 5-6 year range (sometimes a few years longer if you are lucky).  They may get a little “squidgy around the edges” as they age. 

-- HG

Q. I have a part of my yard that needs to have a professional layout a design and try to reclaim an ugly old and many problem spot. Have several problems and it is a small area, but the first you see when you go out the front door. Have no clue how to find someone who is not geared to redesigning a big project for someone with a lot more resources than I have. Any suggestions you can give me would be appreciated. Colleen Regan - University Place, WA

A. Reading between the lines of what you are saying I am guessing you may be intimidated by the thought of hiring a landscape architect.  Another option to a landscape architect (who must be pass a licensure exam after attending an accredited landscape architecture program and have a minimum of seven years in any combination of training and education) is a Professional Landscape Designer.  These individuals are certified by the Association of Professional Landscape Professionals. They must minimum of two years of professional landscape design experience and submit samples of their work and experience as well as other pertinent information about their business.  These are designers who may be better suited to your needs.  Information about the Washington Chapter (including a way to find a designer) can be found at their website:  http://www.apldwa.org/

-- HG

Q. I have a 4 yr old weeping golden chain tree.  It bloomed the first year it was planted but not since.  It’s in a shady area with morning sun, get good watering and in well-drained soil.  This year I thinned a bit to try and make it less dense.  Other than lack of golden chains, it appears healthy.  What is the secret to get it to bloom? Barbara Wray - Puyallup

A.  Golden Chain tree (Laburnum spp.) blooms on wood from the previous season so the only time you can prune it without risk of removing flowers is after it flowers in the spring.  Many people wonder what these trees are because they are so striking with their golden yellow pea shaped flowers that hang in long panicles thus the common name.   It is always a good idea when purchasing flowering shrubs to ask the vendor the best time to prune them.  But when in doubt most winter and spring flowering shrubs bloom on previous seasons wood.  This is what allows them to bloom so early in the season.  They begin forming flower buds during the summer months.  On the other hand shrubs that bloom in the summer and fall generally bloom on new growth from the current season.  This is what delays the bloom later into the season.  Usually the mode of flowering is a result of evolutionary factors that influenced the shrubs in their native habitat. 

-- HG