Growing Together: The secrets to tulip success

Did you know that in 17th century Holland, you could buy a house or a farm field for a handful of tulip bulbs? Not because property was dirt cheap, but because tulips were that valuable.

The Dutch people had become infatuated with the flower bulbs that originated in Turkey, and by the 1600s, tulips were so pricey that the average bulb sold for the equivalent of a tradesman’s yearly salary. The tulip financial bubble eventually popped, of course, but what became historically known as tulip mania endured for the Dutch.

When tulips are blooming in spring, many of us wish we had planted more of them last fall. Tulips follow the rule of other perennials: the best time to dig, divide or plant is during the season opposite the perennial’s bloom time, which is why we plant tulips or divide the bulbs in fall.

Although fall is the time for planting new tulips, the care we give existing tulips now in spring determines whether they’ll bloom well next year, or whether the bulbs will weaken and fizzle out. Large, healthy bulbs have enough food and energy stored within to ensure vigorous blooms the first spring. Our job as gardeners is to rebuild the bulb’s energy after blooming.

Tulip botany helps us understand why spring care is vital. As tulips finish their spring flowering flush, the leaves of the plant feed the underground bulb in preparation already for next year’s growth. Forming deep within the bulb are tiny leaves and future flower buds. The potential size and strength of these tiny flowers-waiting-to-happen depends on good nutrition. After their spring work is completed, tulip leaves turn yellow, wither, and die away.

Here’s what to do in spring so tulip beds will continue to flourish:

• While tulips are blooming, keep them well-watered during dry periods, especially if they are planted near a building’s foundation, where the soil tends to dry out.

• As soon as tulip flowers fade, remove them by cutting right below the withered blossom. The flower stalk can be left on. Removing the spent flowers prevents a seed pod from forming, which needlessly saps energy.

• Fertilize the tulip bed with a granular, well-balanced 10-10-10 fertilizer at the rate of one-third to one-half cup per 10 square feet of flower bed. This is a vital step in providing the nutrition tulips need to replenish themselves after spring’s flower flush. Water after fertilizing, to activate the granules.

• Water-soluble fertilizer, such as Miracle-Gro, can be used in place of granules if desired, applied every 10 days while leaves are green and active.

• Tulip leaves are manufacturing food while they’re green and healthy. Don’t remove or cut back any foliage.

• Leaves will eventually turn yellow, then brown and withered. When leaves are dry and crisp, they can be removed, and the bulbs then remain dormant from midsummer on.

• Some gardeners plant annual flowers close to the tulips to provide color after the tulip foliage disappears.

• Tulip varieties differ in their longevity. Darwin hybrids tend to thrive from year to year better than others.

• Tulips bulbs remain healthier if soil is rich in organic material like compost or peat moss. Heavy clay and light sandy soil both benefit from incorporating two-to-three inches of organic material. Established tulip beds can be top-dressed with organic material, and lightly worked into the surface.

• Tulip bulbs require digging and dividing every two to four years on average, in September or early October.

• Give tulips another application of fertilizer in fall, as they produce roots in preparation for the following spring.

Fielding questions

Q: What kind of grass or weed is this in our lawn? It’s by our driveway in front of our house. What can we use to curb it? — Roxane Eckroth, Wahpeton, N.D.

A: Wide-bladed, weedy grasses are sometimes all mistakenly called “crabgrass.” One way to differentiate is by seeing when they begin growth. Your photograph, taken now in early May, shows well-established grass plants, green and growing.

Actual crabgrass is an annual grass that restarts from seed each spring, that doesn’t germinate until soil temperatures are warm, meaning plants aren’t large and visible until sometime later in June.

Weedy grasses beginning strong growth in May are almost always perennial grasses like quackgrass, arising early from well-established, winter-hardy root systems. Other features identifying the grass as quackgrass are white underground rhizomes and “clasping auricles,” which are tiny, fingerlike projections where the leaf blades attach to the stem.

Unfortunately, there isn’t anything that will kill quackgrass without also killing the desirable lawn grass. You can spot-spray the patches of quackgrass with a grass-killing herbicide, such as glyphosate (original Roundup) and then reseed after the grass is dead-brown. Quackgrass often regrows from latent underground buds after the tops have died, so patiently allowing regrowth followed by a second spray is a more thorough method.

As an alternative to chemicals, quackgrass can be smothered with cardboard or black plastic held in place for most of the growing season and then reseed in September, if quackgrass has died.

When a scientist finds a marketable product that selectively kills quackgrass without harming the lawn, they will be heroes to lawn owners. And rich.

Q: We’re trying to thin out our strawberry patch. Should I remove the older, more established plants or the smaller, newer ones? Last year, our berries were small and I think it was because the plants are so close together. — Lucia Schroeder, Glyndon, Minn.

A: When renovating a strawberry bed, the newer plants are used, instead of the old.

Strawberry beds remain productive for about two or three seasons before plants become crowded and berry size declines. Then, healthy young plants can be dug and replanted at proper spacing in May.

Two planting systems can be used. The matted-row system is commonly used in home gardens. Rows are spaced 3 to 4 feet apart and plants are set 18 to 30 inches apart within the row. Allow runners to form a mat 15 to 18 inches wide, with plants 4 to 6 inches apart.

The second method, called the hill system, produces large, high-quality berries. Space rows 2 to 3 feet apart, with plants 12 to 15 inches apart within the row. Remove runners as they appear, so plants remain as individual “hills.”

Q: Do you have any suggestions for potato bugs? We’ve used various powders with no success. My grandfather once said the only sure cure for potato bugs is to take one at a time and put it between your thumb and pointer finger and squeeze it. Is that the only cure? — Jim and Judy Frisk.

A: Potato bugs are also known as Colorado potato beetles, which is often the name we find when searching insecticide labels.

Potato beetles have developed resistance to many common insecticides, which then give little or no control. The key is to rotate between several different chemicals including spinosad, permethrin, and Sevin. You might especially try spinosad, which is a relatively new insecticide and has been used with good results by many, as the beetles might not have developed as much resistance to it yet.

You mentioned hand-picking. That is still a legitimate method, walking the potato patch and picking larvae and beetles as you find them. My dad said that as a kid that was his job, and they would drop the beetles in a can of kerosene. Since many of us don’t have kerosene on hand, drop them in a container of soapy water instead.