I have a raised planter bed on the side of my house that I've planted a few Japanese Maples and Ginkgo's. The bed is 3' x 15' and the plants range in size from 1ft to 4 ft right now. But I'm really curious if the bed is big enough for the FUTURE. I was thinking I would "have" to widen the bed in order to give the plants enough room as they grow. But then I figured they would just adapt to the size of the bed... Any insight? Would you leave it be or extend it? Any one willing to help an amateur in Austin? Here are the tree's I have planted. Ginkgo Jade Butterfly - should get up to 9ft Ginkgo Chase Manhattan - should get up to 6 ft Butterfly - should get up to 8 ft Shin Deshojo - should get up to 12 feet Mikawa Yatsubusa - should get up to 8 ft
I bet that your planter is great looking in Spring. Any pictues? How do you handle soil/media maintenance? After a while the soil will be depleted and compacted. The plants can manage those conditions for a while but eventually they become weakened and susceptible to pathogens. That has been my experience. Also if you're thinking long, long term i think that the plants will need pruning. Root pruning and branch pruning seem to be required to maintain containerized plants for extended periods.
Hi bkb, how tall is the raised bed and more importantly what is underneath it? Is it on top of concrete or asphalt, or is it just soil beneath with the roots free to go where they will? This will make a big difference regarding how large the trees will grow and whether they should be treated as in a large container or open ground. Also where are the trees planted in relation to one another? For example 'Shindeshojo' grows about as tall as wide, but 'Butterfly' will be a more upright shape. As PtB suggested a picture would help.
Just as an aside, it may take a long time for mikawa yatsubusa to get up to 8 ft. Mine has grown about 6 cm in 2.5 years!
Great questions friends. I'll try and answer them one at a time. I'll try and post up pictures ASAP. This will hopefully answer some questions on placement. My thoughts on placement were Tamukeyama, Shin Deshojo, Ginkgo Chase Manhattan, Butterfly, Ginkgo Jade Butterfly. In this setting, I'll alternate tall plants with shorter dwarf forms. The soil consists of 1 part perlite, 4 parts pine bark, 2 parts top soil. I was hoping to aerate it every year with a tree garden hose aeration unit. and try to work organic compost into the soil at the same time. The raised bed is 2 feet tall with 1 1/2 foot of the above mix. Below it is texas native soil which is sandy loam. Since I have 5 plants in 3'x15' space, each plant should get about a 3'x3' square of soil. I know they'll compete, but I figured they could live harmoniously. I'm not opposed to selectively pruning the tops as they grow larger. But I'd rather not dig them up once they are established.
I should think the roots will spread outwards until they reach the sides of the bed, then go down and out into the surrounding soil. The plants will probably grow to a similar size and have a similar growth rate as they would in open ground. Long term it would probably be best to put three trees in the bed, rather than five, based purely on the width. (Unless you revised the choice to include more dwarf and fastigiate forms.) I can't really say about the ginkgos, as I don't grow them, but 'Tamukeyama', 'Shindeshojo' and 'Butterfly' would fill up a 15 feet wide space by themselves quite easily after a few years. Perhaps you could plant three trees you wish to keep in the bed long term, and put two others inbetween them and near the front of the bed in root control bags or similar, such that you could remove them easily and safely once the bed became overcrowded.
Root feeders don't work, if you are talking about a metal rod with holes that shoot water out of the sides this will have no effect on the texture of the potting medium between the channels blasted through it by the water pressure. Your first main problem will be the decomposition, leaching and settling of the mostly soil-less mix you are using.
Yes, a mainly soil based mix would be best in this type of bed for a permanent planting. (edit - and you could add mulch annually rather than trying to work compost into the soil)
Soil based makes sense to me as well. If container-to-earth contact is mostly continuous on the bottom capillary action will alleviate the drainage/aeration problem. Dr. Whitcomb talks about the feasibility of this method in "Production of Landscape Plants"
Thanks for the recommendations. I'll look at reducing the number of plants. Do you think having the Shin Deshojo 2 feet from the foundation is too close? Should I move it out some more? Any thoughts on what type of soil mix would be better for this type of planter. We have very alkaline soils and water here because of the limestone. I used pine bark in order to keep it as acidic as possible.
I like this article: Suitable garden soils for a Japanese maple. The author claims limestone soils up to a PH of 7.5 are fine for Japanese maples, I have no idea how alkaline the soils in Austin are, but your regular garden soil is probably fine. It wouldn't hurt to add a little pine bark (or other organic material) to the soil, say 20%, and the bark is good for mulch too. The Shindeshojo roots won't damage the foundations if that is a worry, and the branches will tend to head for the light, away from the wall and to either side. It is just down to personal preference if two feet is far enough out. Good luck, sounds like the bed will look nice.
