Yes, you can plant them in spring or as soon as your soil is workable and no longer frozen. Planting ASAP is certainly preferrable than storing them for any length of time. In fact I'd consider potting them up as soon as I received them rather than waiting until too much later to plant outside. But they may not do much this season. Ornamental alliums have a relatively early bloom season and do need a winter chill period, which is why they are included with other spring flowering bulbs for planting in the fall. Frankly, I am a little suprised at any reputable bulb dealer selling the bulbs this late (or early, depending on your perspective :-)). Generally alliums offered outside of the normal fall planting period are presented as started bulbs in pots. FWIW, 'Ivory Queen' is a great selection. It is an early bloomer and has a low profile, making it a good choice for the front of the border. And it produces a large bloom, given the size of the plant. It also has an ability to maintain good foliage appearance, a real plus for an allium. Most alliums, by the time they are ready to bloom, are adorned with some really ratty looking foliage, making it necessary to hide their bases amongst other plantings.

I'm hoping you have a place in your garden to the north east. You'll need early morning sun followed by 'filtered light' to prevent those flabby leaves from frizzling. And wind shelter. Some sun shading may be necessary. In your potting mix use a sharp grit, some leaf mold or ordinary potting mix, and keep it on the dry side. If those bulbs have few to no roots they can't cope with lots of water. They'll rot. While the leaves are still there plant only so the white of the stalk and the bulb is covered. When the leaves die off, plant into a deeper pot about three to four inches down, then 'plunge' the pot into a cool patch of garden with a 'Here I am!' label. Up to the rim of the pot. You're trying to keep the firmness up in the little bulbs, and it's usually easier to do that underground. If you want to mulch to retain soil moisture, so long as the drainage is good, that should be ok. While they're still green, do a foliar feed - diluted half, or even quarter strength. Something suitable for tomatoes (the potash is helpful). Stronger will not be better... You might have to wait one to two years to get any flowering response. My zone 9 is very different from yours. We rarely get the temperature extremes. However, if you can provide relief from high soil temperatures and excessive dryness over the dormant period you can probably grow Hyacinths, although they may not sustain the 'full on' glory of the first season. A short-lived treasure, perhaps.

I have no bulbs for trade, nor advice but I can tell you what bulbs I successfully grow in zone 8b SW GA. What grows for me in the hottest, most humid part of the state are certain daffodils: jonquillas, triandrus types, miniatures and cyclamineus types; hyacinths do well for me. Those are the early spring bulbs. Late spring: agapanthus, amaryllis, Longiflorum/Asiatic hybrid lilies, and Calla lilies. In summer: crocosmia, crinum, caladium, colocasia, Oriental/Trumpet lilies and their hybrids; cannas In late summer and fall: lycoris and sternbergia I've grown tulips and freesias. Like yours they didn't come back. Tulips are too much trouble, freesias prefer greenhouse treatment. The alliums I planted didn't grow, either. Glads do come back for me sometimes but not always. Bulbs that have not done well for me include dahlias, tuberoses and muscari. I saw blooms but not increase. Recommended bulbs that I have not tried include leucojum and zepharanthes, but I have seen these growing in gardens in Grady County. BrentandBeckysBulbs have their summer bulbs on sale until June 1. Nell

Planting potted started plants in the spring should work out just fine. Gladiator is said to be hardy through zone 4. Generally it is cheaper to plan ahead and plant dormant bulbs in the fall, but well done started plants, though generally much more expensive, also work.