Termite-resistant mulches

What kind of mulch can I use that won’t attract termites? I have seen shredded rubber; but that won’t add anything organic to my soil. Are there other alternatives?

Apart from being unattractive and difficult to remove, shredded rubber may also build up heat over root zones. ‘Cypress’ mulch is said to repel insects while the aromatic compounds are still fresh, but it has a few issues as well. Cypress can be expensive and the harsh orangey color can clash with flower and foliage colors. Hard wood mulch is less expensive and has a deep brown color that is more attractive. Finely milled forms are very desirable for their appearance and trait of breaking down into humusy soil.

If termites are a problem for you, and they can be if you have sandy soil or live along the river, you may want to stick with chopped leaves as a mulch. Leaves, the choice mulch at nearly all botanical gardens, do what mulch is supposed to do, and then some. They will insulate the soil to keep soil temperatures even, suppress weeds, hold moisture and attract earthworms. Earthworms tunnel and create oxygen spaces for roots and leave worm castings that are rich in nutrients. Chop and pick leaves up with a mower or use a chipper/shredder; then add them to beds in the fall. You can also stockpile chopped leaves for spring application. Best of all, they are free.

Attracting humming birds

What can I plant to attract humming birds? I have tried the plastic feeders but they just fill up with ants.

A top recommendation for humming bird flowers is the native columbine (Aquilegia canadensis). The dangling, coral colored blooms open in May along with the return of hummers. Let these flowers reseed among your flower and shrub beds where they seem to always look at home. They will grow in sun or part shade. Most tubular flowers attract hummers; I have seen them nectaring at fuchsia, perennial salvias (Salvia ‘Caradonna’, ‘May Night’, etc.), annual salvias like ‘Victoria Blue’ and ‘Lady in Red’, as well as on beebalm (Monarda didyma) and all Lobelias. If you have plenty of sun, try some of the more exotic annual salvias like ‘Black and Blue’ or ‘Argentinean Skies’. These salvias love heat and respond to a sunny location by growing four feet tall and blooming until frost. Hummers seem to like a sunny place to sit and are attracted to horizontal lines like clothes lines. Perhaps a coated wire stretched across the flower bed would provide such a respite. Don’t forget to provide dripping water for birds on dry days. My neighbor used to hang a plastic milk jug over the bird bath and allow water to drip from a pin prick in the bottom.

Sucker punch

How can I keep suckers from coming up around crab apples and other ornamental plants each year? They get so thick that it becomes a major chore.

Certain plants, crab trees chief among them, do sucker freely. If the plant is a lilac, forsythia, shrubby dogwood or such, it is best to leave the new growth from the base and remove old growth (thick gray stems) to keep the plant healthy and to produce more fruit or flowers. But crab trees, contorted filberts and so on need to be kept free of basal root suckers to achieve the look for which you planted them.

Suckers on these ornamental plants are caused by two circumstances; one is damage to roots near the soil surface and the other is growth of the rootstock coming from below a graft.

• Try to buy plants that are grown on their own roots.
• Avoid tilling or digging below a young tree to avoid root injury.
• Cut the suckers back early, before they are all leafed out and competing with the graft subject.
• Try placing a collar of heavy black landscape fabric or MulchMat over the suckering zone to shut out light. Secure plastic with a thin layer of mulch, but don’t pile mulch around the base of any tree.
• There is a Sucker Stopper product available that can be sprayed over the cuts to prevent resprouting for the season. Visit montereylawngarden.com to evaluate the merits of this rather expensive product.

Delphinium dilemma

I love the look of foxglove and delphinium but mine never look like the ones in magazines. How can I keep them from becoming puny and spindly?

Does it help to know you are not alone? The only foxglove that I have found to be perennial is the pale yellow Digitalis grandiflora. It prefers some afternoon shade and very rich soil. The same can be said for delphinium. A good rule of thumb for assessing the suitability of your soil for these fussy plants is whether or not your soil would grow good tomatoes. In other words, heavily amended, humusy, soil that is like chocolate cake in texture. You can have some success with delphinium for several years if you find a spot that is protected from wind, gets lots of morning sun, some afternoon shade and you spend at least one full season preparing the site by adding compost, leaves and rotted manure. Plant delphiniums in the spring, beginning with small, first year plants. (The big, already blooming ones are not coming back.) Stake plants early when the bloom stalks appear the following spring. Delphinium will simply not tolerate drought. Foxglove can take slightly drier soils, but still prefer moisture.

Other cottage garden favorites with an upright habit include hollyhocks (Althea), false indigo (Baptisia australis), perennial salvia (Salvia nemerosa) and French catmint (Nepeta siberica ‘Souvenir de Andre Chaldron’). Incidentally, a few hostas like H. ventricosa have sturdy, vivid blue blooms that remind me of delphiniums in August.

Japanese beetle control

How can I control Japanese beetles? Are the traps the best method or is grub control on my lawn?

Traps for Japanese beetles may seem like they are working when the bags fill up with dead beetles, but those results are misleading. The pheromones used in the traps will attract beetles from up to a mile away; probably many more than you would ordinarily have. They also attract only males, not egg laying females.

Controlling the adult beetles should consist of hand picking when possible. It is especially important to watch for and remove the very first beetles that arrive since these earliest scouts ‘call’ other beetles to your plants. If your infestation is too large to hand pick and you determine that you must use an insecticide, buy only the smallest amount of Sevin possible and spray only the beetles themselves. The spray will not keep, so don’t mix more than you can use at once. Avoid spraying plants during the hottest part of the day. Sevin dust is even better than the liquid because the dust will enter the insect’s spiracles (breathing holes) for more effective control. Wear a mask when using Sevin dust. Try to clean up the dead beetles that fall so that birds will not eat them.

You can also control the grubs that turn into adult beetles while they are still in the lawn. Be aware that controlling grubs in your own lawn will not protect you from beetles that fly in from other lawns and fields. Amazingly enough, most of the grub controlling insecticide that is applied in the Midwest is totally wasted because people apply it at the wrong time. Television commercials encourage us to buy it in the spring. Garden centers sell it in the spring. And the directions on the bag say to use it when the grubs hatch, which most folks think is in the spring. Wrong. Grubs hatch in August and September, a few weeks after the adults lay their eggs. And since the product takes several weeks to build up in the roots of grass plants, it should be applied in July! When you read the directions carefully you will also learn that the product must be watered in well to be taken up by roots. If the area that you are treating can’t be watered, or at least half an inch of rain is not eminent; don’t bother wasting your time and money.

Pale pin oak

Can you tell me why my pin oak is yellow and getting thin? It is in good soil and gets plenty of sun. I water it when the weather is hot.

Pin oak (Quercus palustris) is an oak that grows in river bottoms and other wet situations, thus the species name palustris, which means ‘of wet meadows’. Pin oaks that are planted on high ground, in heavy, alkaline soils, or in dry sandy soils will become chlorotic and decline. There are iron treatments that can be injected into the tree’s trunk or drenched into the soil around the tree but they are expensive and inconsistently effective. Further, if your soil is sandy, the soil drench treatment will leach right through it and out of the root zone. There seems to be dramatic variation among pin oak individuals, since someone else’s tree may perform in the same environment where yours would not.