Horticulture Guy

Q. With watering restrictions almost a certainty, is there a proper way to prepare your lawn to go dormant or for a reduced watering schedule so the lawn will come back next year healthy. Steve Ostrander -Graham, WA

A. As far as restrictions being a “certainty” please reference the article this past Tuesday in the News Tribune “Water supply should last through summer” by Susan Gordon. Whether or not we have water restrictions many people still wish to conserve water. The summer lawn is often a large percentage of most homeowners’ water bill. Summer dormancy is a condition cool season lawn grasses are genetically programmed for. The simple answer is: if you have a healthy lawn it will be prepared for summer dormancy. So for example if you have weed problems they will be exacerbated by the dormancy period. This is because the advantage most weeds have is that they do not go dormant in heat and drought the way lawn grasses do. Weeds usually have deeper roots like tap roots and other water gathering strategies. In addition many weeds use a different biochemical pathway to absorb carbon dioxide from the atmosphere. Carbon dioxide is a necessary component of the production of sugar in photosynthesis. The weed’s pathway is a much more efficient pathway than the one the cool weather grasses’ at absorbing carbon dioxide. This means the pores of the plants (called stomates) do not need to stay open as long to gather carbon dioxide. When the pores are open the plant loses water through evapotranspiration. So weeds loose less moisture in hot/dry weather and thus their advantage. Thatch is another important element in summer lawn water conservation. A ½ inch thatch layer is healthy and normal and will serve to keep the soil below the lawn from allowing moisture to evaporate. Using a mulching mower to send the grass clippings back into the lawn is also helpful in reducing water usage since it serves as a mulch. Also keep your lawn length high as we approach the summer – around 2-½ inches. Fertilize the lawn in the spring with a slow release fertilizer but do not fertilize in the summer. This is especially important if you use inorganic fertilizers. These fertilizers are salt based and can draw moisture away from the roots if they remain in the soil unused.

-- HG

Q. Last year, after their blooming, we pruned our evergreen and deciduous azaleas back pretty severely. They were really getting carried away and we felt we needed to curb them. As a result, they REALLY got carried away. We were afraid if we re-pruned them, we would be pruning off all the flower buds. What to do? When is the latest that we can prune and still manage a good flowering? Thanks. Marty Williams - – Sumner, WA

A. There seems to be a theme here today – growth mismatch. In this case it seems the growth is incompatible with the gardener. You mention that you felt they needed to be curbed. Why did you feel that way? Obviously the azaleas have a different opinion. If you are dealing with an issue of space then you may want to consider moving the azaleas to a part of the garden where they can spread their leaves. Why fight with them? Repeat after me – “Free The Azaleas”. If on the other hand you can reach a compromise with the azaleas, and still want to manage their size, limit your pruning to 1/3 of the growth. You have about a month after the azaleas bloom to prune without the potential for removing buds that are forming for next years display.

-- HG

Q. Worked with you (I’m still in the pit orchestra) at the Music Playhouse many years ago. I’m an avid reader of your articles and have attended a couple of your presentations at the fair grounds. I have a dwarf (semi?) 4-way apple tree that I planted in 1990 or so. It’s annual fruit production is awesome and I always have to shore up its spindly, finger-sized branches to hold the fruit. It is being overcome by a cedar tree and must be moved to survive. I have a great spot picked our for it, but want to know if now is a good time to move it. Also, the tree is about 6-7 feet tall. Can you estimate the extent of its root growth? I don’t want to damage any more than I have to. Don Miller – University Place, WA

A. This is not the ideal time to move the tree. The best time to move it is when it is dormant. The extent of the root growth is approximately a foot beyond the drip line of the tree (dripline is where water would trip off if the canopy of the tree were an umbrella). If you hope to move it yourself you may wish to root prune the tree around the drip line. This means you take a spade now and make a circle around the tree cutting in as far as the spade will go without drawing up soil. This will sever any roots further out and consolidate the new root for the eventual move. Then in the late fall after it is dormant (dropped all its leaves) you can move the tree. You may even consider contacting a tree service with a tree spade. Make sure they have a certified arborist on staff to oversee the process.

-- HG

Q. Hello Peter, My Beauty Plum, Italian Prune, and Stellar Cherry trees all have noticeably smaller diameter rootstock than the grafted on main trunk. These trees are all 5-8 years old and the difference seems to be getting more pronounced. Is the rootstock likely to catch up or is the upper tree going to snap off in a windstorm someday? When selecting fruit trees, should I be choosing trees with matching root stock and upper tree diameter sizes? My apple tree trunks and rootstocks all look normal with no noticeable differences in diameters. Thanks, Henry Raynor - Puyallup, WA

A. I guess the first thing I should do is explain why fruit trees need rootstock in the first place. People have grafting the scions of cultivated varieties onto rootstock for over two thousand years. The Greeks were known to graft varieties that they chose for taste or fruit sized and grafted them onto seedlings produced from local fruit trees of the same species. This gave the cultivars the vigor of the local trees with the benefits of the cultivated variety (cultivar). Over the centuries the grafting has become more complex and is used to control the growth habit of the cultivar including size and fruit production, disease or weather resistance. Grafting also allows people testing new cultivars to bring seedlings into production much faster than if they grew on their own roots to maturity. This can save years on the release of a new cultivar. For home orchards many rootstock have been developed for varying degrees of growth limitation. When you see dwarf, semi-dwarf or standard this relates to the rootstocks ability to control the ultimate size of the tree. Also rootstock does not necessarily have to be from the same species as the scion wood although they are usually within the same genus. Many times there can be graft incompatibility and the union between scion and rootstock breaks down. Compatibility and effects of a particular rootstock on a particular scion cultivar is determined by field tests. There is no other way to determine compatibility. What you are describing is a reverse taper, which indicates that the scion is outgrowing the rootstock. This is the case when a very vigorous scion is placed on a very dwarfing rootstock and causes a growth mismatch. I talked with Sam Benowitz of Raintree Nursery (raintreenursery.com) and he said that although this is not common he has heard this can happen when Western Sand Cherry Rootstock (Prunus besseyi) is used. Since you don’t know what the type of rootstock was used it is difficult to say anything for certain other that there is a growth mismatch. Reputable growers would use proven compatible rootstock. The reverse taper is not necessarily an indication that there is a graft incompatibility. And no the problem won’t reverse but is likely to become more pronounced with time since you are dealing with different growth rates (implying time). But it is likely your trees will remain healthy and upright for many years to come. So get used to living with your “bipolar” tree. If nothing else you have a conversation piece for backyard parties.

-- HG

Q. I have a Siam Tulip – of the Ginger Family of plants? The name of the plant on the mailing carton was con-? I looked thru my agriculture Encyclopedia under Ginger and Siam (Siamese) and the plant wasn’t there. The Encyclopedia didn’t have the mailing carton name in it. The blant “tuber” or whatever it is called is rather a dark tan and bumpy, snarly looking. How does one plant this? I had what I thought was root planted into the soil, leaving the “stems” and “top” above the soil- nothing happened in three weeks time so now the whole plant is covered lying sideways. Please tell me what to do with this. Helen Preisz – Packwood, WA

A. Cutting to the chase I believe you have Curcuma alismatifolia which an Ornamental Ginger (Zingiberaceae) as you indicated. It has a rhizome-tuber. Not very common and I have to say that I am not impressed with whomever was your source for this plant since it seems it was not labeled well and didn’t include growing instructions. It is considered a tender tropical and is quite uncommon outdoors except in the Deep South since it is only hardy to USDA zones 8 and higher. If you plan on growing it outdoors here I would suggest that you bring it in for the winter. Packwood does not benefit from the moderating effects of the Puget Sound and I am sure it would not make it through the winter. On the other hand it makes a good greenhouse or bright sunny window plant. I have never seen this plant but from what I understand the soil should be kept moist (not wet) at all times. The plant dislikes being left high and dry. The rhizome should be completely planted below the soil line. If you have more or less than about 3 inches of soil above the rhizome I would repot it.

-- HG

Q. We have had orchard bee blocks in place for several years now and all the holes seem to be getting filled up. Is there a time when we should clean them out or should we just hang more blocks? Seems like the nests are always still hatching or being refilled. We don’t want to kill our precious bees, that’s for sure. Thanks. Marty Williams – Sumner, WA

A. I think you are much better off putting out more blocks. If the old blocks become unsuitable to the bees over time they will abandon the old blocks and move to the new ones. Wood blocks are not easy to clean. What would make them unsuitable would be parasite or disease. Professional growers 5/16 paper tube inserts in wood blocks so they can replace them each year. This is also how they are sold. Although orchard bees prefer wood they will also nest in plastic drinking straws that have been folded in half, taped together and inserted into a soup can that has been mounted on an outdoor wall. Knox Cellars produces many of these products so you don’t have to. Their products are carried at many independent local garden centers. You can contact them at: Knox Cellars, 25724 NE 10th St., Sammamish, WA 98074

-- HG

Q. My husband has a problem with moss growing in our back yard 100 by 100 feet. He has used moss killer, dug up the moss, and now reseeded it. He wants to know how to prevent future moss growth. Should he use lime to sweeten the soil? There is some shade in the yard, but mostly it is an open flat yard with good drainage, no standing water problems. Linda Shehan – Lakewood, WA

A. When moss out competes a lawn this means that the conditions are not favorable to the lawn. You say there is good drainage and sun, but is there good air circulation? This could be the most difficult to change since it could mean changing wood fences to chain link or some open form, or removal of dense shrubs. The soil could also have some compaction, which would favor the moss. If you have had a lot of foot traffic or vehicles have been on the lawn then core aeration would be needed. I would also recommend testing the soil for pH and major nutrients Nitrogen, Phosphorus and Potash and apply lime or sulfur (ph up or down respectively) and nutrients as needed. A pH in the range of 6-7 would be ideal for the lawn. There is also a natural moss and algae killer on decks, fences, roofs, and lawns made from 2% herbicidal soap that may be useful until you can improve the lawns growing conditions.

-- HG

Q. Question: Hello again Peter, My question is, “Where’s the bees?”. My fruit trees are all in various stages of bloom. I check them daily and have yet to see a bee or any other insect working the blossoms. I use no sprays or chemicals in my yard. Are my garden labors to be “fruitless” this year? Thanks, Henry Raynor – Puyallup, WA

Q. Hello Peter, I read your column quite often and am always learning something more than I thought I knew! I really don’t have a question exactly… I work for garden retailer and have been in the garden business for about 16 years now and I get concerned every spring for our busy little bee friends. Every spring customers come in wanting to spray their trees with something to kill pests. I explain to them that during the bloom time it is important not to spray insecticides into the fruit trees as it is so damaging to the bee population.(not to mention the lady bugs) Can you please pass this on in your column, and maybe include a few good choices for pest control(natural) to boot?? Thanks muchly, Lori Walters – Eatonville, WA

A. Well there seems to be some buzz (sorry I couldn’t resist) about this subject so let’s see what I can do to help unravel this complex issue. Even if you don’t spray in your yard Henry it doesn’t mean someone else in your neighborhood that “shares” the bees with you has not. Also development of land continues to diminish nesting sites for native bee populations. Native bees are great because they are much more tolerant of our weather conditions and will be out in earlier, in cooler and wetter weather than their domesticated cousins. And let’s not forget about the earliest of the bees the orchard mason bee, which comes out about the time Pieris (Lily of the valley shrub) starts blooming. Lori you are quite correct about spraying plants when they are blooming especially with non-selective insecticides like organophosphate based sprays (eg. Malathion, Sevin). Products will have warnings on the label when they are toxic to bees and should indicate not to spray on flowering plants when bees are present. So the best advice is to avoid spraying when plants are in bloom. But for cases where it is necessary let’s look into other options. Bees are active from approximately 6am to 8pm. The actual times are weather and day length dependent. You may see suggestions that low toxicity and natural sprays can be used when the bees are not active as long as they dry before bees are active again. This can work as long as the formulation is not somehow brought back to the hive. Dust or micro-encapsuled formulations are more likely to stick to the bees and be brought back to the hive. Even one of the safest natural insecticides, neem oil, can create problems because of its insect growth regulating properties. Although the spray won’t affect the worker bees, I have heard that it can coat the pollen which is then fed to the developing brood of bee larvae that won’t mature due to the growth regulator. Species-specific sprays like Bt (Bacillus thuringiensis) can be used since they are specific to certain species of insects (Lepidoptera, Diptera, and Coleoptera - moths butterlies, beetles, flies) and must be ingested by the larval stages of the species. For more specific information on this subject contact your County Agent/Master Gardeners at 1-877-WSU-MG4U.

-- HG

Q. Because I have very limited areas of ample sunlight in my yard, I plan to do some container (vegetable/herb) gardening this year. The concern I have is about how to keep the critters (squirrels especially) away from my young sprouts. The last time I did container gardening, those guys ate up everything. I don’t want to have to shoot them. Pam Duncan-Pierce - Federal Way, WA

A. Since I don’t want to see you walking around your yard wearing a squirrel skin cap like a Davy Crockett wannabe let’s see what we can do. The reason squirrels dig in containers is to store away food for a later date. This is where the majority of the damage comes from. A way to stop this digging behavior is to use chicken wire or hardware cloth. In your case you would need to cut it out into a circle and place it on the top of the soil in the container. You can seed right over this. If you are planting a transplant make a hole in the center large enough to fit the it through. Now although the nibbling could be the squirrels or it could also be rabbits (scwewy wabbits). In either case you can find repellents with natural ingredients that can be used on herbs and vegetables like Shake-Away Squirrel Repellent or Hot Pepper Wax.

-- HG

Q. I recently transplanted some huckleberry bushes. In the process it was necessary to cut the large taproot. Do I need to prune back the foliage? If so how much? Donald Bishop - University Place, WA

A. This can be explained using the concepts “supply & demand”. As any plant grows, both the shoots and the roots maintain equilibrium of supply & demand. The roots are supplying water, minerals and nutrients to the shoots and leaves (that in turn become suppliers of sugars generated from photosynthesis – to themselves, flowers fruits and the roots – but I digress). Roots at any given time have just enough capacity to supply the leaves the water and nutrients they need. It is not “cost effective” for the plant to maintain more capacity. If you remove some of the existing capacity the supply is diminished. A percentage of root system is always lost during transplanting. So the demand for water and nutrients from the would be greater than the supply. Different plants respond differently when this happens. Some wilt in an effort to reduce demand. Others slow down non-critical functions like flower or fruit production. One solution as you aluded to, is to prune back some of the foliage (shoots) to decrease the demand. When possible this is a good solution. You will have to estimate the percentage of root loss and remove the equivalent roots. Not an exact science by any means but plants will adjust as long as you are in the ballpark.

-- HG