The days are getting shorter, and the temperatures are finally getting cooler, meaning fall has arrived. While many of our gardening activities are starting to wind down, it’s time to start thinking about planting our spring-blooming bulbs. Bulbs such as crocus, tulips, daffodils, as well as a host of others, can provide a burst of color early in the year before many of our other landscape plants begin blooming.
When should spring-blooming bulbs be planted?
The ideal time to plant bulbs is approximately four to six weeks before the ground freezes, around mid-October to early November. This will give the bulbs time to grow roots before winter sets in. However, any time before the ground freezes will do. It’s better to get your bulbs in the ground than try to store them overwinter.
When choosing which bulbs to plant, pay attention to flowering times. By combining early-, mid-, and late-blooming bulbs, you can have a floral display from early March through June. Also, take flower height into consideration and how they will fit into your landscape.
Bulbs can be purchased from various places, including garden centers, nurseries, box stores, and online retailers. Online retailers often have a much wider selection of species and cultivars to choose from. Regardless of where you get your bulbs from, try to order or purchase them early for the best selection.
If you are purchasing bulbs in-person, select bulbs that are firm, solid, and free of soft spots or signs of disease. Size is also important. The bigger the bulb, the better the floral display. When selecting bulbs, choose the largest bulbs you can find for that particular cultivar. Once you purchase or receive your bulbs, keep them in a cool, dry place until you are ready to plant.
Where should spring-blooming bulbs be planted?
Most spring-blooming bulbs prefer full to part sun conditions. However, early-blooming spring bulbs will often bloom before many trees leaf out. Therefore, it may be possible to plant them under trees or shrubs that would otherwise produce too much shade to grow plants that need full sun or partial shade.
If you decide to place bulbs under trees, be careful not to disturb the tree’s root system too much (don’t till the soil). Early blooming bulbs like crocus, winter aconites, snowdrops, Siberian squill, and early maturing daffodils are good options.
Additionally, bulbs will grow best in well-drained soils. If soils remain wet for extended periods of time, the bulbs may rot. Organic matter such as compost or peat moss can be added to the soil to help improve soil drainage.
You also want to think about what your landscape will look like after your bulbs are done blooming. Planting with other perennials and shrubs can help hide the foliage of the plants after the blooms fade. Annual flowers can also be planted to fill in areas after bulbs have died back for the year.
How do I plant spring-blooming bulbs?
Bulbs have the biggest impact when planted in groups or clusters. Plant larger bulbed species like tulips and daffodils in groups of at least five bulbs and small bulbed species like crocus in groups of at least 25 bulbs.
When it comes time to actually place your bulbs in the ground, pay attention to your planting depth. Packages of bulbs should indicate how deep bulbs should be planted. As a rule of thumb, bulbs should be planted two to three times as deep as they are wide.
This means some larger bulbed plants such as tulips and daffodils should be planted 6 to 8 inches deep, while smaller bulbs such as crocus should be planted 3 to 4 inches deep. When placing your bulbs in their holes, make sure to plant the nose (pointed end) up and the root plate (flatter end) down.
A variety of different tools, from bulb planters to trowels and bulb augers that attach to drills, can be used to dig holes for planting bulbs. Holes can be dug individually, or if you are going to be planting many bulbs in an area, you can dig the entire bed to the appropriate depth. Then place your bulbs where you want them and cover them with the soil you removed.
After you’ve planted your bulbs, water the area well so the soil will settle around your bulbs and provide moisture so they can begin root growth. If the weather is dry, water as needed. Bulbs can also be covered with two to three inches of mulch. This will help retain soil moisture and minimize temperature fluctuations during the winter.
Fertilizing spring-blooming bulbs?
Traditionally it has been recommended that phosphorous, often in the form of bone meal, be added to planting holes to help encourage root growth of bulbs. However, in most cases, this is unnecessary because soils generally have sufficient phosphorous levels in them. Instead, conduct a soil test to see if any additional phosphorus is needed in your soils.
Plants can be fertilized once they begin to emerge in the spring with a 10-10-10 or a bulb fertilizer. However, don’t fertilize once they have started flowering. Fertilizing during flowering can lead to the development of bulb rot which may shorten the life of your plants.
Preventing squirrels and chipmunks
Squirrels, chipmunks, and other rodents may dig up and feed on newly planted bulbs, particularly tulips. One way to protect your bulbs is to place chicken wire or hardware cloth over the soil and anchor it to the ground using landscape staples and cover with mulch. This will make it difficult to dig up the bulbs.
The metal can be left in place, and your bulbs will grow up through the holes (provided they are big enough). It can also be removed in the spring before foliage begins to emerge.
Another option is to grow plants that are toxic like daffodils (due to the alkaloid lycorine) or are otherwise unattractive to them.
After your hard work this fall, you can sit back and relax and enjoy a colorful spring.
Good Growing Tip of the Week: Selecting a site that provides some shade during the middle of the day can often help prolong the life of your bulb’s blooms.
References and for more information
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Meet the author
Ken Johnson is a Horticulture Educator with University of Illinois Extension, serving Calhoun, Cass, Greene, Morgan, and Scott counties since 2013. Ken provides horticulture programming with an emphasis on fruit and vegetable production, pest management, and beneficial insects. Through his programming, he aims to increase backyard food production and foster a greater appreciation of insects.