Allergy Free Gardening

In order to be a good tree to grow in a lawn it needs a number of things going for it. In particular a good lawn tree:

1. Should be deciduous, meaning it should loose all of its leaves in the winter. This will let in light in the wintertime, when light levels are lowest. Deciduous trees also do not block any warming winter sunlight from reaching the house. Trees on the south or east sides of any house should always be deciduous, never evergreen.

2. Should have roots that do not creep upward into the lawn where they'll be hit by lawnmowers. Roots that grow up into the lawn are a real pain, hard to get rid of, and will easily ruin a lawnmower.

3. Should be attractive, or why else even plant it?

4. Should be fairly easy to grow, not too fussy. Always select trees that are know to be disease resistant.

5. Should be able to adapt to the irrigation a lawn will receive. Certain trees grow well in lawns and others, such as oaks, do not. Plant lawn trees that will thrive in a lawn area, even if it is frequently irrigated.

6. Should be a type of tree that will not have a negative allopathic effect on the lawn. For example, eucalyptus or walnut trees produce a substance that kills off other plants below them.

7. Should produce shade that is not too deep. No grass can grow in the deepest shade. Branches on lawn trees should ideally be kept fairly high.

8. Should not produce a lot of allergenic pollen. There's no point in planting a tree that will make you sick every year.

*Note: No lawn tree will grow well when it is young if the grass is allowed to grow right up to its trunk! I can't stress this enough. A young tree in a lawn should have an area underneath it that is kept totally grass-free for the first 4-5 years of the tree's growth. If lawn is permitted to grow right next to the trunk of a young tree, the tree's growth will almost always be stunted. Even after this period of time it is better to either keep the area immediately under the tree grass-free, or to plant a low-growing groundcover under it.

Trunks of young trees should never be hit with weedwackers. String- trimmers ruin the tender bark of many young lawn trees, and then stunt their subsequent growth. Keep a clean area a minimum of 3'wide under any new lawn tree.

Even though a lawn has shallow roots and there is little point in watering lawns much deeper than a foot, trees will develop deep roots. To make sure your new tree grows those deep, drought resistant roots, give it a really good soaking once a month from spring until fall. Just put a garden hose near the base of the tree, turn it on low, and let it soak for a long time.

Watch mulch around the trunks of young trees! Mulching trees is a good idea but keep the mulch a few inches away from the actual trunk of the young tree. In the wintertime, especially where there is snow cover, it is a darn good idea to put a wrap of ¼ inch mesh chicken wire around the trunk, to keep mice and rabbits from eating the tender young bark. Many a new tree is killed because of wintertime damage to the trunk from rodents.

If you live in an area where the winter temperatures get below zero F, it is a good idea to paint the trunks of new lawn trees white. The white paint will reflect the winter sun, and will keep the sap from warming up and starting to flow in the middle of winter. Painted trees are much less likely to get "winter sun scald," which is what they call it when the bark cracks and splits open, usually on the south side of the trunk. Use indoor grade white latex paint for this, and it is perfectly okay too, to paint some of the larger branches. This painting can be repeated each fall with good effect until the tree is about 7-8 years old. As the trees mature their bark will thicken and toughen up, and will naturally be more resistant to freezing and the winter sun.

Make sure to fertilize the new trees twice each season. Use a fertilizer high in N, nitrogen, in the springtime, and a fertilizer low in nitrogen and high in potassium in the fall. Lawn grass that grows under trees may well need a bit of extra fertilizer through the growing season, as the tree roots will absorb much of the lawn fertilizer as well.

There are devices with long, hollow spikes on them that screw on the end of a hose. You put the fertilizer for the tree in these contraptions, shove the spike down deep into the tree's root zone, and turn on the hose. This is a good way to fertilize lawn trees.

Existing trees and planting new lawns

Many a nice lawn tree has been killed when the owner decides to plant a new lawn, and hauls in extra topsoil to spread. If you cover the roots of a tree with several inches of additional soil, you may easily smother the tree roots, killing the tree. If the soil around an existing tree needs to be raised, then you need to build a "tree well," an area around the tree, at least four feet wide, where the original soil level is maintained. This is especially important with oak trees, which will quickly die if the soil level is raised right up to the trunk.

Manure and lawn trees

Never put manure right up to the trunk of a lawn tree. Fresh manure in particular is especially toxic to young trees. I have seen some pretty nice, large trees killed when their owners mulched them with a thick layer of supposedly "well-cured" horse manure. Even with compost, don't place it right next to the trunk of the tree!

First, a dozen lawn trees to avoid planting if possible:

1. Fruitless mulberry trees: roots break lawnmowers and these trees really pump out the allergenic pollen. Shade is also too deep for lawns.

2. Sweetgum trees: big roots that poke out of the lawn.

3. Pine trees: root problems and pollen too.

4. Sycamore trees: usually grow way too large for most yards and they produce fuzz that makes people itch.

5. Cedar trees: a female cedar is a nice, pollen-free tree, but grows way too large for most houses and yards.

6. Magnolia trees: these have shallow roots and if you ever have to rototill your yard, if you have a magnolia tree in the lawn, you'll be sorry. Shade is too dense too for most lawns.

7. Lombardy poplars: these common trees grow fast and die young, leaving you with a huge mess. They also are male and produce lots of pollen.

8. Olive trees: unless it is a Swan Hill or some other non-flowering olive, this one will cause all kinds of allergies. The olives are a big mess too.

9. Walnut trees: nothing grows well under them and they produce lots of pollen and also smelly walnut fruit husks that draw flies.

10. Brazilian Pepper trees: roots are a problem for mowing, the shade is too deep for lawns, and they cause skin rashes and other allergies.

11. Seedless or fruitless Chinese Pistache trees: big producers of the most allergenic pollen. Slow to leaf out in spring.

12. Catalpa trees: slow to leaf out in spring and fast to lose their leaves in the fall. No real fall color at all and they are known to shed considerable amounts of allergenic pollen each spring.

Twenty-five Recommended Trees for your Lawn

1. Red Maple 'Autumn Glory': Zones 3-9. a large, rounded, handsome female, pollen-free tree, loses its leaves, easy to grow in bluegrass lawns. Great fall color.

2. Red maple ''October Glory': Zones 3-9 a female, pollen-free tree, does especially well in lawns and does not cast a deep lawn killing shade.

3. Red maple 'Bowhall,' Acer rubrum 'Bowhall,' is an attractive, pollen-free deciduous female tree, with excellent fall color. It grows narrowly upright and is a good lawn tree for smaller yards. Shade is not dense.

4. Crabapple 'Molten Lava,' Malus species, Zones 4-9. A smaller, very pretty, flowering crabapple tree, to 10' tall, with great flowers in spring and small red fruits in fall. Does fine in well-drained lawns, and is an especially disease resistant tree.

5. Crabapple 'Dolgo, Malus 'dolgo,' Zones 3-9, Pink buds open to fragrant, white flowers in late spring. Glossy, dark green foliage turns yellow in the fall and has good disease resistance. Large, almost florescent, bright red fruit ripening in early summer is excellent for crabapple jelly. A hardy tree with a spreading, upright and open habit. Does well in bluegrass lawns.

6. Crabapple 'Red Splendour.' Malus species, Zones 3-8. Greenish-red leaves with rose-pink flowers. Small red fruit stays on the tree well in to the winter. Good resistance to disease. An upright growing smaller crabapple tree, good in lawns.

7. Crabapple 'Snowcloud,' Zones 4-8, profuse double white flowers, mostly pollen-free and fruitless, bright green leaves, smaller tree, to 20 feet tall. Good in lawns.

8. Crabapple 'Sugar Tyme,' Pale pink buds open to fragrant, showy white blossoms that cover the tree in spring. A bounty of small, persistent, bright red fruit are produced in the fall and attract birds. This vigorous tree has crisp, dark green leaves and an upright, oval habit. One of the most disease resistant flowering crabapples. Good in lawns. To 20 feet tall.

9. Flowering plum: Prunus species, zones 4-10, a pretty, easy to grow tree, loses its leaves in fall, flowers in the spring, grows fast and likes frequent irrigations, as in a lawn. Shade is not dense.

10. Apricot trees, Prunus species, Zones 4-10: attractive, loses its leaves in fall, easy to grow in western areas, blossoms smell great, and the fruit is good. Should be pruned so that it is not difficult to mow under. Does not cast a dense shade. Good fall color too.

11. Fuyu persimmon trees, Diospyros kaki, Zones 4-10: slow growing, very attractive bark and leaves, shade not dense, fruit is beautiful, sweet and excellent, tree is female and pollen-free. Incredible fall color.

12. Pineapple Guava tree, Feijoa sellowiana, Zones 8-10, small evergreen tree. Best grown as a multi-trunked tree, to 18' tall, gray-green attractive leaves, white-red flowers, sweet green fruit. With age the tree becomes more and more attractive, the bark ever more interesting.

13. Honeylocust trees, Gleditsia triacanthos, all Zones, a nice, medium-sized shade tree. Loses its leaves in fall, grows well in lawns, and does not cast a deep grass killing type of shade.

14. Variegated Box Elder, Acer negundo 'Variegata', an attractive, smaller three-leafed maple tree, with beautiful variegated green and white leaves. Deciduous, female and pollen-free, easy to grow, and does well in lawns. Shade not dense.

15. Fringe tree, Chionanthus virginicus, Zones 5-10. If you can find one that has small black fruits on it, then it is a pollen-free female tree, a much desired lawn tree. Roots go down and stay down, foliage is very attractive, leaves lost in winter, attractive, lightly fragrant bright white flowers, grows well in lawns. Shade not dense.

16. Sourwood tree, Nyssa sylvatica, Zones 4-9. A small to medium-sized lawn tree, deciduous, excellent fall color. Female sourwood trees are pollen free; look for the exceptional cultivar called 'Miss Scarlet,' which has no pollen, terrific red fall color, and has attractive small ornamental blue fruit. These trees thrive in acid soils and will not do well with alkaline soil.

17. Japanese Raisin Tree, Hovenia dulcis, Zones 8`-10. The female trees have small, sweet, raisin-like fruit and are pollen-free. Raisin trees have beautiful leaves, are deciduous, grow well in lawns, and do not cast a deep shade.

18. Hardy Rubber Tree, Eucommia ulmoides, best in zones 5-7, is a large shade tree that does not cast deep shade. If you can find a fruiting tree, it will be female and pollen-free too. Roots stay down and tree grows well in bluegrass lawns.

19. Pomegranate tree, Punica granatum, Zones 7-10, makes a beautiful, small lawn tree if grown as either a single-trunked tree, or as a three-trunked tree. Pomegranate thrives where summer heat is high. Loses its leaves in fall, bright yellow fall color, shade not dense, attractive orange flowers and red fruit. Will grow well in a fescue, Bermudagrass, or St Augustine lawn.

20. Bougainvillea, Zones 9-10. Not normally thought of as a tree at all, a bougainvillea can easily be trained into an unusual and quite beautiful small lawn tree. The best way to do this is to pound a strong 8' metal stake, several feet deep into the ground, and then plant three one-gallon bougainvillea plants around the stake. Trim the plants back to one or two of the longest, most vigorous branches, and weave these up the stake. It takes about a year to develop this into a tree form. Keep the trunk leaf-free and shear the top several times a year for a lollypop shape. Best cultivars for this are 'San Diego Red' or the variegated 'Raspberry Ice' bougainvillea. There are some fantastic bougainvillea trees at Disneyland.

21. Quaking Aspen, 'Pendula,' Populus tremuloides 'Pendula' grows in all Zones. This is a medium-sized, pollen-free, female, weeping aspen tree, very attractive, good fall color, easy to grow, and is fast growing. Doesn't cast a deep shade and grows well in most lawns.

22. Black Poplar, 'Theves' Poplar, Populus nigra 'Afghanica' or P. n. 'thevestina' is an attractive, medium-sized, tall, narrowly upright shade tree, winter hardy in all zones. 'Theves' Poplar is female, pollen-free, and has bright yellow fall color. Good in lawns where a narrow tree is needed.

23. 'Noreaster' Poplar, Populus 'Noreaster' is a good, larger shade tree for lawns. 'Noreaster' is a sterile female tree, so no seeds and no pollen. Does well in most bluegrass lawns and is winter hardy in even the coldest zones.

24. Japanese Paper Mulberry trees, Broussonetia kazinoki, are separate sexed and if you can find a fruiting tree, it will be pollen-free. These do not cast deep shade like most of the other mulberry species and will thrive in lawns in most cool areas. Winter hardy zones in 5-9.

25. Paperbark maple, Acer griseum, Zones 4-8. This small to medium-sized maple tree has exceptionally beautiful bark and is totally handsome at all times of the year. Paperbark maple doesn't cast a deep shade and lawn will grow quite well underneath it. Best in soils that are well drained and slightly acidic.