Arizona Bulb Growing Guide: How to Grow Bulbs in the Low Desert
Flowering bulbs add dependable color, fragrance, and beauty to the garden, whether they bloom in spring, summer, or fall. However, growing bulbs in the low desert of Arizona presents a unique set of challenges, particularly in terms of timing. In this Arizona bulb growing guide, you’ll learn when and how to plant flowering bulbs in the low desert, which types grow well here, and tips to ensure success.
For in-depth planting details and bulb-specific timing, be sure to check out the full Arizona Bulb Planting Guide: Low Desert Flowering Bulbs
What we will cover in this bulb growing guide:
- What Do I Mean by “Bulbs”?
- Timing Is Everything: Don’t Plant Fall Bulbs Too Soon
- Quick Tips for Planting Bulbs in the Low Desert
- Flowering Bulbs That Grow Well in the Low Desert
- Bed Preparation and Location for Bulbs
- Planting Bulbs in the Low Desert
- Water and Fertilizer
- What to Do After Flowering: End-of-Season Bulb Care
- Can You Grow Tulips in Arizona?
- Final Thoughts and Resources to Learn More
What Do I Mean by “Bulbs”?
In gardening, the term “bulb” is often used as a catch-all for several types of underground storage structures that develop into flowering plants. While they all store energy and are planted similarly, they aren’t all true bulbs. Here’s a breakdown:
- True Bulbs (e.g., tulips, daffodils, hyacinths)
Made up of layered scales (like an onion) with a central flower bud. - Corms (e.g., gladiolus, freesia, ranunculus)
Solid, swollen stem bases that store nutrients. Often replaced annually. - Rhizomes (e.g., iris, canna lilies)
Horizontal underground stems that produce roots and shoots at nodes. - Tubers (e.g., dahlias)
Thick, underground stems with growth points or “eyes” that sprout new plants.
In this guide, “bulbs” refers to all of these types, since they’re planted and cared for in similar ways in the low desert.
Timing Is Everything: Don’t Plant Fall Bulbs Too Soon
One of the most important things to understand about growing bulbs in the low desert is when to plant them. Most flowering bulbs require a period of cooler soil to develop strong roots before blooming. If planted when it’s too hot, bulbs may rot, dry out, or fail to sprout.
In the low desert, wait to plant fall bulbs until daytime temperatures are consistently below 90°F (32.2°C). For most areas, that means late October or even November, later than you might expect if you’re used to planting bulbs earlier in other climates.
Before planting, read this post on Ordering Bulbs for Fall Planting for recommended varieties and pre-chilling timelines tailored to desert gardeners.
Quick Tips for Planting Bulbs in the Low Desert
- Choose the right varieties. Look for bulbs that can handle our short winters and mild chill hours. Some bulbs, such as tulips and hyacinths, require pre-chilling before planting.
- Pre-chill when needed. Many spring-blooming bulbs benefit from being refrigerated for 6 to 10 weeks before planting. Store in a breathable paper bag, away from fruit (which releases ethylene gas that can damage the bulb).
- Prepare well-draining soil. Bulbs do not like soggy roots. Raised beds or amended garden soil with compost and perlite can help improve drainage. Learn how to improve desert soil in this Soil Guide for Raised Beds and Garden Beds.
- Plant at the correct depth. A general rule is that the depth should be 2–3 times the height of the bulb, but check specific requirements for accuracy.
- Water after planting, then sparingly. Too much water in warm soil can lead to rot. Once cooler weather arrives, regular winter rain and occasional watering are usually sufficient. For more guidance, read my Desert Watering Guide.
Flowering Bulbs That Grow Well in the Low Desert
Here are a few reliable options to try:
- Daffodils – One of the easiest bulbs to grow in the desert.
- Freesia – Fragrant and colorful, perfect for containers.
- Ranunculus – Stunning blooms, easy to grow.
- Iris – Many types do well here, especially bearded varieties.
- Calla Lilies & Cannas – Summer-blooming bulbs that thrive with enough water.
- Rain Lilies – Tolerant of hot, dry summers and rewarding after summer rains.
For planting details, spacing, and care tips, grab my Flower Planting Guide. A helpful reference for growing flowers and bulbs in the low desert.
If you’re planting bulbs seasonally, my Perpetual Flower Planting Calendar is a great tool to stay on track.
Bed Preparation and Location for Bulbs
Proper site selection and bed preparation are crucial to successful bulb growing in the low desert. Taking time to prep well will improve drainage, boost bloom quality, and help bulbs last longer in the soil.
Choosing the Right Location
- Full sun is best for most flowering bulbs during winter months, especially for strong blooming and compact growth. Some varieties tolerate partial shade, but flowering may be delayed.
- Avoid areas with tree or shrub roots, which will compete for water and nutrients.
- Stay away from caliche or hardpan. Bulbs need loose, well-draining soil to thrive.
- Watch for Bermuda grass. If it’s growing in your chosen area, try to eliminate it completely before planting.
Prepping the Bulb Bed
- Add organic matter. Southern Arizona soils benefit from generous amounts of organic amendments. Coarse peat moss or shredded bark improve water retention and provide a slightly acidifying effect that bulbs appreciate.
- Skip fresh manure. It can burn tender bulbs and encourage rot. Use only well-composted manure and apply it at least six weeks before planting.
- Improve drainage. In heavy clay or silt soils, mix in 1–2 inches of sand throughout the bed.
- Add phosphorus. Bulbs respond well to phosphorus for root and flower development. Apply bone meal according to package directions, and work it into the soil below the bulb planting depth.
- Mix amendments deeply. Incorporate all materials several inches below the planting zone so bulbs can access nutrients and benefit from improved soil texture where they’ll actually be growing.
- Flush salts before planting. After preparing the bed, water thoroughly with 3–4 inches of water to leach salts from the soil. Let the bed dry enough to be workable before planting.
Planting Bulbs in the Low Desert
Planting bulbs correctly sets them up for strong roots and beautiful blooms. Here are the key things to keep in mind when planting bulbs in desert gardens:
- Choose the right location. Bulbs need well-draining soil and perform best in full sun to partial shade. In shady areas, flowers may bloom a bit later, helping to extend the bloom season.
- Group by height. Since bulb plants vary in height, group taller varieties toward the back and shorter ones in front for the best display.
- Plant in clusters. Bulbs look more natural and full when planted in clumps, drifts, or groups, rather than in single rows.
- Depth matters. As a general rule, plant bulbs two to three times as deep as the bulb is tall. Check the Bulb Planting Guide for specific depths by variety.
- Pre-chill when necessary. Tulips, hyacinths, and other bulbs that require a cold period will perform better if chilled in the refrigerator (vegetable drawer) for 3–4 weeks before planting in late fall. Keep them away from fruit while chilling.
- Water thoroughly after planting. Soak the soil deeply right after planting to settle the bulbs and ensure moisture reaches the root zone. After that, water sparingly until green growth appears.
- Mulch to protect. Apply a layer of wood chips or other organic mulch to help conserve moisture, moderate soil temperature, and suppress weeds.
Tip: Wait to plant fall bulbs until daytime highs stay below 90°F for the best results.
Water and Fertilizer
Once growth is underway, bulbs don’t need daily watering. In full sun, a deep watering every 7–10 days is usually enough. In shaded areas, you can often extend the interval to every 14–20 days. Be sure to water deeply each time so moisture reaches the entire root zone.
Fertilize bulbs two or three times during the growing season to support healthy growth and strong blooms. Choose an organic fertilizer that’s low in nitrogen—too much nitrogen encourages excess leafy growth at the expense of flowers. Look for a fertilizer with more phosphorus and potassium to support blooming and bulb development. This is the one I like to use.
What to Do After Flowering: End-of-Season Bulb Care
Once your bulbs have finished blooming, how you care for them depends on your goals and your garden plans.
- Growing as annuals (like tulips)?
After flowering, you can remove and compost the bulbs once the blooms fade. These are often treated as one-season plants in the low desert. - Hoping for naturalization or regrowth?
Deadhead spent flowers but leave the foliage in place. Let the leaves die back naturally to return energy to the bulb or corm. If they’re in a dry, well-drained area, many types can stay in the soil over summer with minimal water. - Want to lift and replant next fall?
Deadhead the blooms and allow the foliage to dry down fully. Once leaves are dry and before triple-digit temperatures arrive, carefully dig up the bulbs or corms. Mature bulbs will have tan to brown outer skins. Trim off dried roots and foliage, and store them in a cool, dry, well-ventilated space—never in a sealed bag or airtight container. - Need to reuse the space for summer flowers?
Consider lifting the bulbs each spring. Prolonged summer moisture can lead to rot in many varieties. Lifting and storing help protect the bulbs and make room for warm-season planting.
Tip: Some bulbs may need chilling before replanting, especially those that require a cold period to bloom. Experiment in your own garden to see which varieties return reliably and which need extra care.
Can You Grow Tulips in Arizona?
Yes—but only with pre-chilling, and usually as an annual. Refrigerate tulip bulbs for 8–10 weeks, then plant when temperatures are under 90°F (32.2°C). Unfortunately, you can’t expect them to rebloom in our climate.
Learn how to grow tulips in hot climates in this guide.
Arizona bulb growing guide: final thoughts and a source to learn more
Bulbs are a rewarding way to add structure and color to your garden, but timing and temperature make all the difference. Wait until it cools off, choose the right varieties, and plant with care, and your garden will reward you with beautiful blooms in the months ahead.
Source:
Cooperative Extension (Publication No. 0382). Bulbs for Southern Arizona. The University of Arizona, College of Agriculture, Tucson, Arizona 85721.
Share This Arizona Bulb Growing Guide
Know someone who wants to grow bulbs in the desert?
Use the buttons below to Pin it or share on Facebook to help others learn when and how to plant flowering bulbs in the low desert.
Leave a comment on Arizona Bulb Growing Guide: How to Grow Bulbs in the Low Desert