Be Inspired Blog - Arizona
Why Do Spring-Flowering Bulbs Need to Be Planted in Fall?
Fall is the perfect time to start planning for beautiful spring blooms! While gardeners in cooler climates may already be planting their spring-flowering bulbs, Arizona's warmer temperatures mean we often need to wait a little longer. The good news? Fall is a wonderful time to explore the many bulb varieties suited to our desert climate, including some that benefit from pre-chilling before planting. With a little planning now, you can look forward to a colorful display when spring arrives!
Why Plant Spring-Flowering Bulbs in Fall
Many spring-flowering bulbs need a period of cooler temperatures to encourage healthy growth and flowering. This process, known as vernalization, helps trigger the development of blooms once warmer spring weather arrives.
In Arizona's low desert, many spring-flowering bulbs can be planted once temperatures cool, generally when daytime highs are consistently below 90°F. However, planting times and chilling requirements vary by variety, and some bulbs, including bearded iris and garlic, can be planted earlier.
Because our winters aren't always cold enough to meet the chilling requirements of certain bulbs, varieties such as tulips, hyacinths, and crocus often benefit from pre-chilling in the refrigerator for approximately 8–10 weeks before planting.
Place bulbs in a breathable mesh or paper bag in your refrigerator's crisper drawer, keeping them away from ripening fruits such as apples, bananas, and pears. These fruits release ethylene gas, which can damage developing flower buds.
After their chilling period, bulbs can generally be planted in November or December, depending on the variety and weather conditions.
Tips for Planting Spring-Flowering Bulbs
A little preparation can make a big difference when planting bulbs in Arizona's desert climate. Start by selecting a location with the appropriate sunlight for your chosen varieties and soil that drains well. Many bulbs prefer full sun to partial shade, although requirements vary.
Working compost into the soil can help improve soil structure and support healthy root development.
Planting Your Bulbs
Once you've chosen your location and prepared the soil, it's time to plant!
As a general guideline, plant bulbs at a depth approximately two to three times their height, measuring from the bottom of the bulb to the soil surface. Always check the planting instructions for your particular variety, as some bulbs and rhizomes require different planting depths.
Place each bulb in the planting hole with its pointed end facing upward and its root end facing downward. Cover with soil and gently firm it into place.
Allow enough space between bulbs to accommodate their mature growth. Smaller bulbs, such as crocus, may be planted approximately 3–4 inches apart, while larger bulbs, such as daffodils and hyacinths, generally benefit from 6–8 inches of spacing. Follow variety-specific recommendations when available.
Garden Design Tip: For a natural-looking display, consider planting bulbs in groups or clusters rather than straight rows. You can also combine varieties with different bloom times to extend your spring flower display. Whether you prefer a formal arrangement or a more relaxed garden style, have fun creating a design that complements your outdoor space!
Fertilizing & Watering
Planting New Bulbs
When planting new spring-flowering bulbs, we recommend E.B. Stone Organics Bone Meal to provide phosphorus and calcium, nutrients that support root development and overall plant health.
If additional phosphorus is appropriate for your soil, mix approximately 1–2 tablespoons of Bone Meal into the soil in each planting hole, following product label directions. Avoid placing concentrated fertilizer directly against the bulb.
After planting, water thoroughly to help settle the soil around the bulbs and encourage root development. Continue to monitor soil moisture, adjusting your watering schedule based on rainfall, temperatures, and the needs of each bulb variety.
Avoid keeping the soil consistently wet, as excess moisture can lead to bulb rot.
Feeding Existing Bulbs
For bulbs already established in your garden, Espoma Organics Bulb-Tone can provide nutrients to support healthy growth and future flowering.
Apply according to package directions and the needs of your bulb variety, typically as new growth begins to emerge. For bulbs that return year after year, feeding at the appropriate time can help replenish nutrients used during their growing and flowering cycle.
After flowering, allow the foliage to remain in place until it naturally yellows and dies back. During this time, the leaves continue producing energy that helps replenish the bulb's reserves for future growth.
Helpful Tip: Arizona soils can already contain significant amounts of phosphorus. A soil test can help determine whether additional phosphorus is needed before applying Bone Meal or other phosphorus-rich fertilizers.
Protecting Your Bulbs from Hungry Critters
You're not the only one who may appreciate your newly planted bulbs! Some animals, including rodents, may dig up or feed on certain bulb varieties.
If digging animals are a concern in your garden, consider planting susceptible bulbs in protective wire baskets or cages buried in the soil. These can help keep animals from reaching the bulbs while allowing roots to grow.
You can also explore animal repellents, such as Bonide Repels-All, when the product label lists the animal and application site you're targeting. Always follow label directions, particularly around edible plants, children, and pets.
Keep in mind that some bulbs are naturally less appealing to certain animals than others.
Growing Bulbs in Pots
Don't have a large garden bed? No problem! Spring-flowering bulbs can also create beautiful displays in containers, making them a wonderful option for patios, entryways, and other outdoor spaces.
Choose a container with adequate drainage holes and fill it with E.B. Stone Organics Rose & Flower Mix. This versatile planting mix can provide a supportive growing environment for your spring-flowering bulbs. Be sure your container drains well, as bulbs don't like sitting in soggy soil.
Plant bulbs at the recommended depth and spacing for each variety. You can also experiment with layering compatible bulbs at different depths, sometimes called lasagna planting, to create a colorful combination of flowers.
For added interest, consider combining bulbs with different bloom times. With thoughtful planning, you can enjoy successive waves of spring color as different varieties come into bloom.
Place your containers where they'll receive the appropriate sunlight, and monitor soil moisture regularly. Container-grown bulbs may need more frequent watering than those planted in the ground, but good drainage remains essential.
Best Spring-Flowering Bulbs for Arizona Gardens
Spring-flowering bulbs offer a wonderful variety of colors, shapes, and sizes. From cheerful daffodils to elegant iris, there's something for nearly every garden style.
Here are some favorites to consider for Arizona's low desert:
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Allium – Distinctive, globe-shaped blooms that add height and architectural interest.
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Anemone – Colorful, delicate-looking flowers that brighten beds and containers.
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Crocus – Charming, low-growing flowers that can benefit from pre-chilling in our warmer climate.
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Daffodil – Cheerful spring blooms, with some varieties better suited to warm-winter climates than others.
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Grape Hyacinth – Clusters of small, bell-shaped flowers that bring beautiful blue and purple tones to spring gardens.
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Hyacinth – Fragrant flowers in a range of colors that generally benefit from pre-chilling in the low desert.
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Iris – Elegant, distinctive flowers available in many colors. Planting methods and timing vary by type.
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Ranunculus – Layers of colorful, rose-like petals that make beautiful additions to garden beds and containers.
With so many varieties to choose from, spring-flowering bulbs offer endless opportunities to add seasonal color and personality to your garden.
Ready to get started? Visit your local SummerWinds Nursery to explore our seasonal selection of spring-flowering bulbs, and let our Trusted Garden Advisors help you choose varieties suited to your garden.
Please note that section varies daily by location. Please contact your favorite SummerWinds location to confirm availablity.
