Daily Archives: July 9, 2008

gardening tips, plant care, soil

Garden coaching

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Right plant-right place

Lately I’m getting a lot of requests for garden coaching. The economy probably has something to do with it. People want to know what plants will thrive in the different areas of their gardens or why something isn’t working. Who can afford to waste $ on the wrong plant in the wrong location?  When I make house calls there are several problems that seem to keep cropping up. Maybe one of these tips will help make your garden grow.

  Poor soil
If your soil looks like a sandy beach, amend it each time you plant something new with organic matter like compost or planing mix. Then be sure to mulch the surface to preserve precious moisture and soil structure and keep roots cool. Yearly, add organic mulch around existing planting keeping the immediate area around the crown of the plant open. If your native soil is just a little on the sandy side, you may not need to amend the soil much before planting but don’t forget that all important mulch. Crushed gravel or cobbles uses as a mulch holds in moisture the same way as bark or compost.

Those of you who live under redwoods may have the opposite problem- heavy clay soil, dense enough to make pottery. Surprisingly, adding organic matter to these soils solves this problem, too. The key is preserving the soil structure fterwards by mulching so it doesn’t pack down every time you water or during the winter rains.

 Not watering deep enough or watering too often
Sure there’s a period of time when you first plant something that you need to water more often until it’s established but even then watering every day is rarely needed. As a rule of thumb, water a new 1 gallon plant when the top 1/2 " – 1" is dry. A newly planted 5 gallon container will need watering when the top 1 1/2 – 2" is dry. A tree or large shrub planted from a 15 gallon container needs watering when the top 2-3" is dry. Hot days as well as shady locations vs sunny sites will all affect how long you can go between waterings.  When you do water apply enough to water the entire root zone deeply. If the water doesn’t penetrate 1-3 ft down, depending on the plant, it will suffer and even die. Drip systems are great if you have them set properly. Don’t waste water by having your timer set for 10 minutes every other day. If you have 1 gal/hour emitters that’s less than 3 cups of water each. How deep is that going to penetrate? Set your system so that each zone gets enough water for long enough to really count. This applies to established low-water use plants, too. They need a deep soak every 2-4 weeks.
One last tip on drip systems: make sure the emitter isn’t right next to the stem or trunk. Plants need water applied at the drip line where the feeder roots are located, not drowning the crown. Move it out as the plant grows and the dripline enlarges.

  Gopher baskets
If you need to plant in gopher baskets, make sure you eliminate the air pockets between the root ball and the side of the basket. Many times I’ve dug around a plant that is not doing well only to find big air spaces down the side of the basket or the planting hole where the soil was not properly tamped down. The roots on that side of the plant will die under these conditions and possibly the whole plants will be killed.

  Right plant-wrong place
Become familiar with the sun patterns of your property during the growing season- spring through fall. Many of us don’t have winter sun and lots of plants can adapt to this but they are more exacting when it come to light requirements during the growing season. It gets pretty hot around here so a spot with sun in the afternoon is fatal to a plant that is not a sun lover. For those optimists out there, those delicate rays that filter through your trees do not constitute a sunny garden. You have bright shade and there are lots of great plants that can provide color and texture in your shady garden. Make sure you follow tip #1 in both spots so your plant isn’t fighting crummy soil on top of everything else it has to handle.

Hopefully, these tips will help make your garden grow better.

gardening tips, landscape design, perennials, trees, trees,shrubs,vines,perennials

Planting under mature trees

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lush plants under mature trees

We live under oaks and are surrounded by redwoods. We know the value of trees in the landscape. Trees shade us in the summer. Their showy blossoms herald a much awaited spring and their colorful foliage in the fall quietly marks the end of the growing season. You can hang a hammock between two of them or tie a rope swing for the kids from a large branch. Yes, trees are our companions, but how can you create a garden under one of them?

Planting under a mature tree can be a challenge. Caution is required to avoid damaging their roots and the plants will need to cope with dry soil, shade, root competition and ever-changing moisture and light conditions. You want both your new plants and your tree to thrive.

Meet your tree’s needs first. Some trees are more agreeable than others about giving up some of their ground. You can still plant beneath trees that are sensitive to having their roots disturbed, but you’ll need to make a few concessions. When purchasing plants to grow under trees, think small. Small plants require a smaller planting hole and this will minimize disturbance to the roots. You may have to buy more plants but you’ll have an easier time tucking them among the roots.
Don’t alter the grade of the soil or change the soil pH very much. Even adding a layer of soil that is more than 2" deep can reduce the amount of moisture and oxygen available to the tree and hinder gas exchange to existing roots, causing trees to suffer or even die.

Only the toughest plants have a chance of surviving among the surface roots of shallow rooted trees. Be careful when disturbing sugar maples, elms. cherries and plums, dogwoods, magnolias, pines and oaks. The majority of a trees roots are small woody roots and fine hair roots that grow within the upper 12-18" of soil and extend far beyond the trees drip line. These roots are responsible for absorbing water and nutrients from the soil.

If you encounter a root larger than 1 1/2 – 2" in diameter while digging a hole for a plant, move the planting hole a few inches away to avoid slicing through the root. You will sever mats of small tree roots when digging, but they’ll regenerate fairly quickly.
To avoid wounding the bark, which may cause insect and disease problems, start planting at least 12" away from the trunk. Oaks, remember, shouldn’t have any plantings closer than 6-10 feet from the trunk and those should be drought tolerant. After planting, water to settle the soil and spread 2-3" of mulch to conserve moisture and keep weeds down. Be sure to keep mulch at least 12" away from the base of the tree. Mulch can hold moisture against a tree’s bark and cause rot and disease.
Trees that will tolerate some disturbance to the root zone include Eastern redbuds( both the green-leafed species and the purple- leafed Forest Pansy ) and red maples ( also a good lawn tree. ).
Common trees that are easy going about planting underneath are crabapples, ginkgos, hawthorns, honey locust, poplars, silver maples and willows.

So what plants will transform your bare patch of hard earth and knobby roots into a shady nook? If you’re going for a lush look, consider hostas and ferns, paired with the hardy geranium Biokova. Other good companions are astilbes with their feathery flower plumes and variegated euonymus fortunei with bergenia or digitalis mertonensis.
Trees with branches limbed high look good with small shrubs planted underneath. Red-leaf barberry can brighten up this spot and also provide fall color. Small nandinas like Harbor Dwarf make a good ground cover and their foliage takes on an orange-red color in winter. Fragrant sarcococca grows well in this situation, too.
Low groundcovers make a simple statement under the crown of a tree. Ajuga, pachysandra and sweet woodruff all grow well here. Or you might like the look of the shade tolerant grass-like plant , cares morrowii ‘Evergold’. This stunning sedge makes a beautiful clump 1-2 ft. high and 2-3 ft wide with dark green leaves and a central band of creamy white.
You can have a beautiful garden under a mature tree by following these tips and conquering this challenging site.